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Proto xylem Stock Photos and Images
Recueil des travaux botaniques néerlandais . tiole is very différent from theother bundles which we found m other species of Botrychium.Its structure is essentially the same as that of the petiolarbundle in the fossil Osmundaceae (Bertrand, 2) although itshows in some points a marked relation to the petiolar bundlesin Todea, as descnbed by Faull (1901). In the very youngbundle there are fourto six proto-xylem groups. In the matureleaf the number is invariably four (Fig. 16) as in Osmunditesskidegatensis. The bundle, however, is not concentric; as isthe case in Osmundaceae (Faull); but the smal Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/recueil-des-travaux-botaniques-nerlandais-tiole-is-very-diffrent-from-theother-bundles-which-we-found-m-other-species-of-botrychiumits-structure-is-essentially-the-same-as-that-of-the-petiolarbundle-in-the-fossil-osmundaceae-bertrand-2-although-itshows-in-some-points-a-marked-relation-to-the-petiolar-bundlesin-todea-as-descnbed-by-faull-1901-in-the-very-youngbundle-there-are-fourto-six-proto-xylem-groups-in-the-matureleaf-the-number-is-invariably-four-fig-16-as-in-osmunditesskidegatensis-the-bundle-however-is-not-concentric-as-isthe-case-in-osmundaceae-faull-but-the-smal-image338139171.htmlRM2AJ3FXY–Recueil des travaux botaniques néerlandais . tiole is very différent from theother bundles which we found m other species of Botrychium.Its structure is essentially the same as that of the petiolarbundle in the fossil Osmundaceae (Bertrand, 2) although itshows in some points a marked relation to the petiolar bundlesin Todea, as descnbed by Faull (1901). In the very youngbundle there are fourto six proto-xylem groups. In the matureleaf the number is invariably four (Fig. 16) as in Osmunditesskidegatensis. The bundle, however, is not concentric; as isthe case in Osmundaceae (Faull); but the smal
![. Fossil plants : for students of botany and geology . Paleobotany. xxv] TUBICAULIS 435 plate with the smallest tracheae at each end. The solid xylem of the stem stele (protostele) has peripheral groups of proto- xylem. Nothing is known as to the form of the leaves, but sporangia similar to those of Etapteris (Zygopteris) were found in association with the stem. It is possible, as P. Bertrand suggests, that Renault's species may be the stem of a Tubicaulis. Tubicaulis. TvhicauUs solenites (Sprengel) Fig. 304. This species from the Lower Permian of Saxony has been fully described by StenzeP. I Stock Photo](https://c8.alamy.com/comp/PG153T/fossil-plants-for-students-of-botany-and-geology-paleobotany-xxv-tubicaulis-435-plate-with-the-smallest-tracheae-at-each-end-the-solid-xylem-of-the-stem-stele-protostele-has-peripheral-groups-of-proto-xylem-nothing-is-known-as-to-the-form-of-the-leaves-but-sporangia-similar-to-those-of-etapteris-zygopteris-were-found-in-association-with-the-stem-it-is-possible-as-p-bertrand-suggests-that-renaults-species-may-be-the-stem-of-a-tubicaulis-tubicaulis-tvhicauus-solenites-sprengel-fig-304-this-species-from-the-lower-permian-of-saxony-has-been-fully-described-by-stenzep-i-PG153T.jpg ". Fossil plants : for students of botany and geology . Paleobotany. xxv] TUBICAULIS 435 plate with the smallest tracheae at each end. The solid xylem of the stem stele (protostele) has peripheral groups of proto- xylem. Nothing is known as to the form of the leaves, but sporangia similar to those of Etapteris (Zygopteris) were found in association with the stem. It is possible, as P. Bertrand suggests, that Renault's species may be the stem of a Tubicaulis. Tubicaulis. TvhicauUs solenites (Sprengel) Fig. 304. This species from the Lower Permian of Saxony has been fully described by StenzeP. I Stock Photo")
. Fossil plants : for students of botany and geology . Paleobotany. xxv] TUBICAULIS 435 plate with the smallest tracheae at each end. The solid xylem of the stem stele (protostele) has peripheral groups of proto- xylem. Nothing is known as to the form of the leaves, but sporangia similar to those of Etapteris (Zygopteris) were found in association with the stem. It is possible, as P. Bertrand suggests, that Renault's species may be the stem of a Tubicaulis. Tubicaulis. TvhicauUs solenites (Sprengel) Fig. 304. This species from the Lower Permian of Saxony has been fully described by StenzeP. I Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/fossil-plants-for-students-of-botany-and-geology-paleobotany-xxv-tubicaulis-435-plate-with-the-smallest-tracheae-at-each-end-the-solid-xylem-of-the-stem-stele-protostele-has-peripheral-groups-of-proto-xylem-nothing-is-known-as-to-the-form-of-the-leaves-but-sporangia-similar-to-those-of-etapteris-zygopteris-were-found-in-association-with-the-stem-it-is-possible-as-p-bertrand-suggests-that-renaults-species-may-be-the-stem-of-a-tubicaulis-tubicaulis-tvhicauus-solenites-sprengel-fig-304-this-species-from-the-lower-permian-of-saxony-has-been-fully-described-by-stenzep-i-image216384892.htmlRMPG153T–. Fossil plants : for students of botany and geology . Paleobotany. xxv] TUBICAULIS 435 plate with the smallest tracheae at each end. The solid xylem of the stem stele (protostele) has peripheral groups of proto- xylem. Nothing is known as to the form of the leaves, but sporangia similar to those of Etapteris (Zygopteris) were found in association with the stem. It is possible, as P. Bertrand suggests, that Renault's species may be the stem of a Tubicaulis. Tubicaulis. TvhicauUs solenites (Sprengel) Fig. 304. This species from the Lower Permian of Saxony has been fully described by StenzeP. I
![. Fossil plants : for students of botany and geology . Paleobotany. xxv] TUBICAULIS 435 plate with the smallest tracheae at each end. The solid xylem of the stem stele (protostele) has peripheral groups of proto- xylem. Nothing is known as to the form of the leaves, but sporangia similar to those of Etapteris (Zygopteris) were found in association with the stem. It is possible, as P. Bertrand suggests, that Renault's species may be the stem of a Tubicaulis. Tubicaulis. TvhicauUs solenites (Sprengel) Fig. 304. This species from the Lower Permian of Saxony has been fully described by StenzeP. I Stock Photo](https://c8.alamy.com/comp/RDF4EA/fossil-plants-for-students-of-botany-and-geology-paleobotany-xxv-tubicaulis-435-plate-with-the-smallest-tracheae-at-each-end-the-solid-xylem-of-the-stem-stele-protostele-has-peripheral-groups-of-proto-xylem-nothing-is-known-as-to-the-form-of-the-leaves-but-sporangia-similar-to-those-of-etapteris-zygopteris-were-found-in-association-with-the-stem-it-is-possible-as-p-bertrand-suggests-that-renaults-species-may-be-the-stem-of-a-tubicaulis-tubicaulis-tvhicauus-solenites-sprengel-fig-304-this-species-from-the-lower-permian-of-saxony-has-been-fully-described-by-stenzep-i-RDF4EA.jpg ". Fossil plants : for students of botany and geology . Paleobotany. xxv] TUBICAULIS 435 plate with the smallest tracheae at each end. The solid xylem of the stem stele (protostele) has peripheral groups of proto- xylem. Nothing is known as to the form of the leaves, but sporangia similar to those of Etapteris (Zygopteris) were found in association with the stem. It is possible, as P. Bertrand suggests, that Renault's species may be the stem of a Tubicaulis. Tubicaulis. TvhicauUs solenites (Sprengel) Fig. 304. This species from the Lower Permian of Saxony has been fully described by StenzeP. I Stock Photo")
. Fossil plants : for students of botany and geology . Paleobotany. xxv] TUBICAULIS 435 plate with the smallest tracheae at each end. The solid xylem of the stem stele (protostele) has peripheral groups of proto- xylem. Nothing is known as to the form of the leaves, but sporangia similar to those of Etapteris (Zygopteris) were found in association with the stem. It is possible, as P. Bertrand suggests, that Renault's species may be the stem of a Tubicaulis. Tubicaulis. TvhicauUs solenites (Sprengel) Fig. 304. This species from the Lower Permian of Saxony has been fully described by StenzeP. I Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/fossil-plants-for-students-of-botany-and-geology-paleobotany-xxv-tubicaulis-435-plate-with-the-smallest-tracheae-at-each-end-the-solid-xylem-of-the-stem-stele-protostele-has-peripheral-groups-of-proto-xylem-nothing-is-known-as-to-the-form-of-the-leaves-but-sporangia-similar-to-those-of-etapteris-zygopteris-were-found-in-association-with-the-stem-it-is-possible-as-p-bertrand-suggests-that-renaults-species-may-be-the-stem-of-a-tubicaulis-tubicaulis-tvhicauus-solenites-sprengel-fig-304-this-species-from-the-lower-permian-of-saxony-has-been-fully-described-by-stenzep-i-image232058130.htmlRMRDF4EA–. Fossil plants : for students of botany and geology . Paleobotany. xxv] TUBICAULIS 435 plate with the smallest tracheae at each end. The solid xylem of the stem stele (protostele) has peripheral groups of proto- xylem. Nothing is known as to the form of the leaves, but sporangia similar to those of Etapteris (Zygopteris) were found in association with the stem. It is possible, as P. Bertrand suggests, that Renault's species may be the stem of a Tubicaulis. Tubicaulis. TvhicauUs solenites (Sprengel) Fig. 304. This species from the Lower Permian of Saxony has been fully described by StenzeP. I
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. THE HOMOSPOROUS LEPTOSPORANGIATM 361 sists of small ringed and spiral elements constituting the proto- xylem, and larger scalariform metaxylem tracheids. In O. cinnamomea, Faull found an internal endodermis and traces of internal phloem, which are quite absent in the other species, where the xylem-masses are in direct contact with the pith. Faull considers the condition in 0. cinnamomea as the primitive condition from which the type found in the other species has been derived by a suppression Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/the-structure-and-development-of-mosses-and-ferns-archegoniatae-plant-morphology-mosses-ferns-the-homosporous-leptosporangiatm-361-sists-of-small-ringed-and-spiral-elements-constituting-the-proto-xylem-and-larger-scalariform-metaxylem-tracheids-in-o-cinnamomea-faull-found-an-internal-endodermis-and-traces-of-internal-phloem-which-are-quite-absent-in-the-other-species-where-the-xylem-masses-are-in-direct-contact-with-the-pith-faull-considers-the-condition-in-0-cinnamomea-as-the-primitive-condition-from-which-the-type-found-in-the-other-species-has-been-derived-by-a-suppression-image216368722.htmlRMPG0CEA–. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. THE HOMOSPOROUS LEPTOSPORANGIATM 361 sists of small ringed and spiral elements constituting the proto- xylem, and larger scalariform metaxylem tracheids. In O. cinnamomea, Faull found an internal endodermis and traces of internal phloem, which are quite absent in the other species, where the xylem-masses are in direct contact with the pith. Faull considers the condition in 0. cinnamomea as the primitive condition from which the type found in the other species has been derived by a suppression
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. THE HOMOSPOROUS LEPTOSPORANGIATM 361 sists of small ringed and spiral elements constituting the proto- xylem, and larger scalariform metaxylem tracheids. In O. cinnamomea, Faull found an internal endodermis and traces of internal phloem, which are quite absent in the other species, where the xylem-masses are in direct contact with the pith. Faull considers the condition in 0. cinnamomea as the primitive condition from which the type found in the other species has been derived by a suppression Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/the-structure-and-development-of-mosses-and-ferns-archegoniatae-plant-morphology-mosses-ferns-the-homosporous-leptosporangiatm-361-sists-of-small-ringed-and-spiral-elements-constituting-the-proto-xylem-and-larger-scalariform-metaxylem-tracheids-in-o-cinnamomea-faull-found-an-internal-endodermis-and-traces-of-internal-phloem-which-are-quite-absent-in-the-other-species-where-the-xylem-masses-are-in-direct-contact-with-the-pith-faull-considers-the-condition-in-0-cinnamomea-as-the-primitive-condition-from-which-the-type-found-in-the-other-species-has-been-derived-by-a-suppression-image232063904.htmlRMRDFBTG–. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. THE HOMOSPOROUS LEPTOSPORANGIATM 361 sists of small ringed and spiral elements constituting the proto- xylem, and larger scalariform metaxylem tracheids. In O. cinnamomea, Faull found an internal endodermis and traces of internal phloem, which are quite absent in the other species, where the xylem-masses are in direct contact with the pith. Faull considers the condition in 0. cinnamomea as the primitive condition from which the type found in the other species has been derived by a suppression
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. THE HOMOSPOROUS LEPTOSPORANGIAT^ 379 of phloem, separated from the endodermis by a broad pericycle. In other species of Hymenophyllum, Boodle (i) found a dif- ferent arrangement of the xylem and phloem. In some cases, e g., H. scabruni, there are two xylem plates, with the proto- xylem elements in the conjunctive tissues between them. In Trichomanes there is also a good deal of variation. Fig. 220, B, shows the structure in T. venosum, a small species from. Fig. 220.—'A, Section of the rhizome Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/the-structure-and-development-of-mosses-and-ferns-archegoniatae-plant-morphology-mosses-ferns-the-homosporous-leptosporangiat-379-of-phloem-separated-from-the-endodermis-by-a-broad-pericycle-in-other-species-of-hymenophyllum-boodle-i-found-a-dif-ferent-arrangement-of-the-xylem-and-phloem-in-some-cases-e-g-h-scabruni-there-are-two-xylem-plates-with-the-proto-xylem-elements-in-the-conjunctive-tissues-between-them-in-trichomanes-there-is-also-a-good-deal-of-variation-fig-220-b-shows-the-structure-in-t-venosum-a-small-species-from-fig-220a-section-of-the-rhizome-image216368649.htmlRMPG0CBN–. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. THE HOMOSPOROUS LEPTOSPORANGIAT^ 379 of phloem, separated from the endodermis by a broad pericycle. In other species of Hymenophyllum, Boodle (i) found a dif- ferent arrangement of the xylem and phloem. In some cases, e g., H. scabruni, there are two xylem plates, with the proto- xylem elements in the conjunctive tissues between them. In Trichomanes there is also a good deal of variation. Fig. 220, B, shows the structure in T. venosum, a small species from. Fig. 220.—'A, Section of the rhizome
. Botanical gazette. Plants. 230 BOTANICAL GAZETTE [SEPTEMBER The number of protoxylem points in the stem stele ranges from 4 to 11, with about 7 as the most frequent number. Sections of the young stem tip show the condition characteristic of Lycopo- dium, in which at about the time of differentiation of the proto- xylem points the metaxylem cells are distinguishable by their large size and lack of protoplasmic content (fig. 2). There are 3 so-called types of stele to be found in L. reflexum: the radial arrangement (fig. 3), the parallel-banded arrangement (fig. 4),. Fig. 5.—L. reflexum: stele Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/botanical-gazette-plants-230-botanical-gazette-september-the-number-of-protoxylem-points-in-the-stem-stele-ranges-from-4-to-11-with-about-7-as-the-most-frequent-number-sections-of-the-young-stem-tip-show-the-condition-characteristic-of-lycopo-dium-in-which-at-about-the-time-of-differentiation-of-the-proto-xylem-points-the-metaxylem-cells-are-distinguishable-by-their-large-size-and-lack-of-protoplasmic-content-fig-2-there-are-3-so-called-types-of-stele-to-be-found-in-l-reflexum-the-radial-arrangement-fig-3-the-parallel-banded-arrangement-fig-4-fig-5l-reflexum-stele-image234428118.htmlRMRHB3CP–. Botanical gazette. Plants. 230 BOTANICAL GAZETTE [SEPTEMBER The number of protoxylem points in the stem stele ranges from 4 to 11, with about 7 as the most frequent number. Sections of the young stem tip show the condition characteristic of Lycopo- dium, in which at about the time of differentiation of the proto- xylem points the metaxylem cells are distinguishable by their large size and lack of protoplasmic content (fig. 2). There are 3 so-called types of stele to be found in L. reflexum: the radial arrangement (fig. 3), the parallel-banded arrangement (fig. 4),. Fig. 5.—L. reflexum: stele
. Fossil plants : for students of botany and geology . Paleobotany. ® © ® ®® ^S) © © - (5^ F. Fig. 631. Gingko biloba. A, A', B. Microaporophylls and sporangia. C. Seed with the outer flesh removed showing an exceptional, tricarinate (radiospermic), form. D. Abnormal megasporophyU; a, vegetative bud; c, collar. E, F. Tracheids from a stem. G. Transverse section of a leaf-vein; px, proto- xylem, t, transfusion-tracheids. (A, B, after Seward and Gowan; D, after Fujii.) the partially modified lamina of a fohage-leaf may bear marginal ovules, the lamina being continuous with the collar (fig. 631, Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/fossil-plants-for-students-of-botany-and-geology-paleobotany-s-5-f-fig-631-gingko-biloba-a-a-b-microaporophylls-and-sporangia-c-seed-with-the-outer-flesh-removed-showing-an-exceptional-tricarinate-radiospermic-form-d-abnormal-megasporophyu-a-vegetative-bud-c-collar-e-f-tracheids-from-a-stem-g-transverse-section-of-a-leaf-vein-px-proto-xylem-t-transfusion-tracheids-a-b-after-seward-and-gowan-d-after-fujii-the-partially-modified-lamina-of-a-fohage-leaf-may-bear-marginal-ovules-the-lamina-being-continuous-with-the-collar-fig-631-image216386408.htmlRMPG1720–. Fossil plants : for students of botany and geology . Paleobotany. ® © ® ®® ^S) © © - (5^ F. Fig. 631. Gingko biloba. A, A', B. Microaporophylls and sporangia. C. Seed with the outer flesh removed showing an exceptional, tricarinate (radiospermic), form. D. Abnormal megasporophyU; a, vegetative bud; c, collar. E, F. Tracheids from a stem. G. Transverse section of a leaf-vein; px, proto- xylem, t, transfusion-tracheids. (A, B, after Seward and Gowan; D, after Fujii.) the partially modified lamina of a fohage-leaf may bear marginal ovules, the lamina being continuous with the collar (fig. 631,
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. THE HOMOSPOROUS LEPTOSPORANGIAT^ 379 of phloem, separated from the endodermis by a broad pericycle. In other species of Hymenophyllum, Boodle (i) found a dif- ferent arrangement of the xylem and phloem. In some cases, e g., H. scabruni, there are two xylem plates, with the proto- xylem elements in the conjunctive tissues between them. In Trichomanes there is also a good deal of variation. Fig. 220, B, shows the structure in T. venosum, a small species from. Fig. 220.—'A, Section of the rhizome Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/the-structure-and-development-of-mosses-and-ferns-archegoniatae-plant-morphology-mosses-ferns-the-homosporous-leptosporangiat-379-of-phloem-separated-from-the-endodermis-by-a-broad-pericycle-in-other-species-of-hymenophyllum-boodle-i-found-a-dif-ferent-arrangement-of-the-xylem-and-phloem-in-some-cases-e-g-h-scabruni-there-are-two-xylem-plates-with-the-proto-xylem-elements-in-the-conjunctive-tissues-between-them-in-trichomanes-there-is-also-a-good-deal-of-variation-fig-220-b-shows-the-structure-in-t-venosum-a-small-species-from-fig-220a-section-of-the-rhizome-image232063780.htmlRMRDFBM4–. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. THE HOMOSPOROUS LEPTOSPORANGIAT^ 379 of phloem, separated from the endodermis by a broad pericycle. In other species of Hymenophyllum, Boodle (i) found a dif- ferent arrangement of the xylem and phloem. In some cases, e g., H. scabruni, there are two xylem plates, with the proto- xylem elements in the conjunctive tissues between them. In Trichomanes there is also a good deal of variation. Fig. 220, B, shows the structure in T. venosum, a small species from. Fig. 220.—'A, Section of the rhizome
![. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 311 to a type of stele consisting of a central core of xylem surrounded by phloem, pericycle, and endodermis. While admitting that steles of this type may sometimes be the result of the modifica- tion of less simple forms, we may confidently regard the protostele as representing the most primitive form of vascular system. The genus Lygodium affords an example of a proto- stelic fern; a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered per Stock Photo](https://c8.alamy.com/comp/PG15KM/fossil-plants-for-students-of-botany-and-geology-paleobotany-xx-recent-ferns-311-to-a-type-of-stele-consisting-of-a-central-core-of-xylem-surrounded-by-phloem-pericycle-and-endodermis-while-admitting-that-steles-of-this-type-may-sometimes-be-the-result-of-the-modifica-tion-of-less-simple-forms-we-may-confidently-regard-the-protostele-as-representing-the-most-primitive-form-of-vascular-system-the-genus-lygodium-affords-an-example-of-a-proto-stelic-fern-a-solid-column-of-xylem-tracheae-and-parenchyma-is-completely-encircled-by-a-cylinder-of-phloem-succeeded-by-a-multi-layered-per-PG15KM.jpg ". Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 311 to a type of stele consisting of a central core of xylem surrounded by phloem, pericycle, and endodermis. While admitting that steles of this type may sometimes be the result of the modifica- tion of less simple forms, we may confidently regard the protostele as representing the most primitive form of vascular system. The genus Lygodium affords an example of a proto- stelic fern; a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered per Stock Photo")
. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 311 to a type of stele consisting of a central core of xylem surrounded by phloem, pericycle, and endodermis. While admitting that steles of this type may sometimes be the result of the modifica- tion of less simple forms, we may confidently regard the protostele as representing the most primitive form of vascular system. The genus Lygodium affords an example of a proto- stelic fern; a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered per Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/fossil-plants-for-students-of-botany-and-geology-paleobotany-xx-recent-ferns-311-to-a-type-of-stele-consisting-of-a-central-core-of-xylem-surrounded-by-phloem-pericycle-and-endodermis-while-admitting-that-steles-of-this-type-may-sometimes-be-the-result-of-the-modifica-tion-of-less-simple-forms-we-may-confidently-regard-the-protostele-as-representing-the-most-primitive-form-of-vascular-system-the-genus-lygodium-affords-an-example-of-a-proto-stelic-fern-a-solid-column-of-xylem-tracheae-and-parenchyma-is-completely-encircled-by-a-cylinder-of-phloem-succeeded-by-a-multi-layered-per-image216385336.htmlRMPG15KM–. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 311 to a type of stele consisting of a central core of xylem surrounded by phloem, pericycle, and endodermis. While admitting that steles of this type may sometimes be the result of the modifica- tion of less simple forms, we may confidently regard the protostele as representing the most primitive form of vascular system. The genus Lygodium affords an example of a proto- stelic fern; a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered per
. Bulletin of the British Museum (Natural History), Geology. MORPHOLOGY AND RELATIONSHIPS OF RACHIOPTERIS CYLINDRICA 57 and situated somewhat nearer the adaxial than the abaxial side (PL 8, fig. 1). This stage is well shown in Williamson Colin, slide 187 and is figured by Seward (1910, text-fig. 305B) and by Scott (1920, text-fig. 156A). Exceptionally the proto- xylem group supplying the branch does not divide into two and occupies a median position in the branch stele. An example of this kind is figured diagrammatically Ky dev.. Fig. 1. Psalixochlesna cylindrica (Will.) Camera lucida outline Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/bulletin-of-the-british-museum-natural-history-geology-morphology-and-relationships-of-rachiopteris-cylindrica-57-and-situated-somewhat-nearer-the-adaxial-than-the-abaxial-side-pl-8-fig-1-this-stage-is-well-shown-in-williamson-colin-slide-187-and-is-figured-by-seward-1910-text-fig-305b-and-by-scott-1920-text-fig-156a-exceptionally-the-proto-xylem-group-supplying-the-branch-does-not-divide-into-two-and-occupies-a-median-position-in-the-branch-stele-an-example-of-this-kind-is-figured-diagrammatically-ky-dev-fig-1-psalixochlesna-cylindrica-will-camera-lucida-outline-image233986764.htmlRMRGK0E4–. Bulletin of the British Museum (Natural History), Geology. MORPHOLOGY AND RELATIONSHIPS OF RACHIOPTERIS CYLINDRICA 57 and situated somewhat nearer the adaxial than the abaxial side (PL 8, fig. 1). This stage is well shown in Williamson Colin, slide 187 and is figured by Seward (1910, text-fig. 305B) and by Scott (1920, text-fig. 156A). Exceptionally the proto- xylem group supplying the branch does not divide into two and occupies a median position in the branch stele. An example of this kind is figured diagrammatically Ky dev.. Fig. 1. Psalixochlesna cylindrica (Will.) Camera lucida outline
![. Practical text-book of plant physiology. Plant physiology. ETIOLATED SEEDLINGS "5 all instances. The etiolated specimens must not be exposed to intense light even for a few minutes and the examination of them should be made by the use of an ordinary candle. The temperature should be kept at 15-20° C, and not so much water will be needed as in plants grown in daylight, owing to the les- —D. :-C.. —B. :-a. Fig. 52. Cross section of portion of normal stem of young Quercus. A, proto- xylem. B, median part of wood-ring in which the medullary rays may be seen. C, cambium. D, bast. E, inner pe Stock Photo](https://c8.alamy.com/comp/RE3EM0/practical-text-book-of-plant-physiology-plant-physiology-etiolated-seedlings-quot5-all-instances-the-etiolated-specimens-must-not-be-exposed-to-intense-light-even-for-a-few-minutes-and-the-examination-of-them-should-be-made-by-the-use-of-an-ordinary-candle-the-temperature-should-be-kept-at-15-20-c-and-not-so-much-water-will-be-needed-as-in-plants-grown-in-daylight-owing-to-the-les-d-c-b-a-fig-52-cross-section-of-portion-of-normal-stem-of-young-quercus-a-proto-xylem-b-median-part-of-wood-ring-in-which-the-medullary-rays-may-be-seen-c-cambium-d-bast-e-inner-pe-RE3EM0.jpg ". Practical text-book of plant physiology. Plant physiology. ETIOLATED SEEDLINGS "5 all instances. The etiolated specimens must not be exposed to intense light even for a few minutes and the examination of them should be made by the use of an ordinary candle. The temperature should be kept at 15-20° C, and not so much water will be needed as in plants grown in daylight, owing to the les- —D. :-C.. —B. :-a. Fig. 52. Cross section of portion of normal stem of young Quercus. A, proto- xylem. B, median part of wood-ring in which the medullary rays may be seen. C, cambium. D, bast. E, inner pe Stock Photo")
. Practical text-book of plant physiology. Plant physiology. ETIOLATED SEEDLINGS "5 all instances. The etiolated specimens must not be exposed to intense light even for a few minutes and the examination of them should be made by the use of an ordinary candle. The temperature should be kept at 15-20° C, and not so much water will be needed as in plants grown in daylight, owing to the les- —D. :-C.. —B. :-a. Fig. 52. Cross section of portion of normal stem of young Quercus. A, proto- xylem. B, median part of wood-ring in which the medullary rays may be seen. C, cambium. D, bast. E, inner pe Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/practical-text-book-of-plant-physiology-plant-physiology-etiolated-seedlings-quot5-all-instances-the-etiolated-specimens-must-not-be-exposed-to-intense-light-even-for-a-few-minutes-and-the-examination-of-them-should-be-made-by-the-use-of-an-ordinary-candle-the-temperature-should-be-kept-at-15-20-c-and-not-so-much-water-will-be-needed-as-in-plants-grown-in-daylight-owing-to-the-les-d-c-b-a-fig-52-cross-section-of-portion-of-normal-stem-of-young-quercus-a-proto-xylem-b-median-part-of-wood-ring-in-which-the-medullary-rays-may-be-seen-c-cambium-d-bast-e-inner-pe-image232417360.htmlRMRE3EM0–. Practical text-book of plant physiology. Plant physiology. ETIOLATED SEEDLINGS "5 all instances. The etiolated specimens must not be exposed to intense light even for a few minutes and the examination of them should be made by the use of an ordinary candle. The temperature should be kept at 15-20° C, and not so much water will be needed as in plants grown in daylight, owing to the les- —D. :-C.. —B. :-a. Fig. 52. Cross section of portion of normal stem of young Quercus. A, proto- xylem. B, median part of wood-ring in which the medullary rays may be seen. C, cambium. D, bast. E, inner pe
. Fossil plants : for students of botany and geology . Paleobotany. ® © ® ®® ^S) © © - (5^ F. Fig. 631. Gingko biloba. A, A', B. Microaporophylls and sporangia. C. Seed with the outer flesh removed showing an exceptional, tricarinate (radiospermic), form. D. Abnormal megasporophyU; a, vegetative bud; c, collar. E, F. Tracheids from a stem. G. Transverse section of a leaf-vein; px, proto- xylem, t, transfusion-tracheids. (A, B, after Seward and Gowan; D, after Fujii.) the partially modified lamina of a fohage-leaf may bear marginal ovules, the lamina being continuous with the collar (fig. 631, Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/fossil-plants-for-students-of-botany-and-geology-paleobotany-s-5-f-fig-631-gingko-biloba-a-a-b-microaporophylls-and-sporangia-c-seed-with-the-outer-flesh-removed-showing-an-exceptional-tricarinate-radiospermic-form-d-abnormal-megasporophyu-a-vegetative-bud-c-collar-e-f-tracheids-from-a-stem-g-transverse-section-of-a-leaf-vein-px-proto-xylem-t-transfusion-tracheids-a-b-after-seward-and-gowan-d-after-fujii-the-partially-modified-lamina-of-a-fohage-leaf-may-bear-marginal-ovules-the-lamina-being-continuous-with-the-collar-fig-631-image231994736.htmlRMRDC7J8–. Fossil plants : for students of botany and geology . Paleobotany. ® © ® ®® ^S) © © - (5^ F. Fig. 631. Gingko biloba. A, A', B. Microaporophylls and sporangia. C. Seed with the outer flesh removed showing an exceptional, tricarinate (radiospermic), form. D. Abnormal megasporophyU; a, vegetative bud; c, collar. E, F. Tracheids from a stem. G. Transverse section of a leaf-vein; px, proto- xylem, t, transfusion-tracheids. (A, B, after Seward and Gowan; D, after Fujii.) the partially modified lamina of a fohage-leaf may bear marginal ovules, the lamina being continuous with the collar (fig. 631,
. Actes du IIIme Congrès international de botanique, pub. au nom de la commission d'organisation du Congrès. Botany. Fig. 7. Lyginodendron oldhamium. Double leaf-tivoce bundle and adjacent tissues in transverse section, .v centripetal ; .r' centrifngal xylem; px proto- xylem; ph phloem of bimdles; //;'- part of pliloem of stèle; ss secretory sacs; pd part of periderm. x abont 40. Welliamson Colin 1884. (Fig. 9), anrt tlie whole cliaracter of tlie highly compouncl leaf was that of a Fern- froiul, whice lias proved to be identical with the type Sphenopteris^Hôiiinghausi. well known in the form o Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/actes-du-iiime-congrs-international-de-botanique-pub-au-nom-de-la-commission-dorganisation-du-congrs-botany-fig-7-lyginodendron-oldhamium-double-leaf-tivoce-bundle-and-adjacent-tissues-in-transverse-section-v-centripetal-r-centrifngal-xylem-px-proto-xylem-ph-phloem-of-bimdles-part-of-pliloem-of-stle-ss-secretory-sacs-pd-part-of-periderm-x-abont-40-welliamson-colin-1884-fig-9-anrt-tlie-whole-cliaracter-of-tlie-highly-compouncl-leaf-was-that-of-a-fern-froiul-whice-lias-proved-to-be-identical-with-the-type-sphenopterishiiinghausi-well-known-in-the-form-o-image237938603.htmlRMRR3137–. Actes du IIIme Congrès international de botanique, pub. au nom de la commission d'organisation du Congrès. Botany. Fig. 7. Lyginodendron oldhamium. Double leaf-tivoce bundle and adjacent tissues in transverse section, .v centripetal ; .r' centrifngal xylem; px proto- xylem; ph phloem of bimdles; //;'- part of pliloem of stèle; ss secretory sacs; pd part of periderm. x abont 40. Welliamson Colin 1884. (Fig. 9), anrt tlie whole cliaracter of tlie highly compouncl leaf was that of a Fern- froiul, whice lias proved to be identical with the type Sphenopteris^Hôiiinghausi. well known in the form o
. Actes du IIIme Congrès international de botanique, pub. au nom de la commission d'organisation du Congrès. Botany. 285. Fig. 7. Lyginodendron oldhamium. Double leaf-tivoce bundle and adjacent tissues in transverse section, .v centripetal ; .r' centrifngal xylem; px proto- xylem; ph phloem of bimdles; //;'- part of pliloem of stèle; ss secretory sacs; pd part of periderm. x abont 40. Welliamson Colin 1884. (Fig. 9), anrt tlie whole cliaracter of tlie highly compouncl leaf was that of a Fern- froiul, whice lias proved to be identical with the type Sphenopteris^Hôiiinghausi. well known in the f Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/actes-du-iiime-congrs-international-de-botanique-pub-au-nom-de-la-commission-dorganisation-du-congrs-botany-285-fig-7-lyginodendron-oldhamium-double-leaf-tivoce-bundle-and-adjacent-tissues-in-transverse-section-v-centripetal-r-centrifngal-xylem-px-proto-xylem-ph-phloem-of-bimdles-part-of-pliloem-of-stle-ss-secretory-sacs-pd-part-of-periderm-x-abont-40-welliamson-colin-1884-fig-9-anrt-tlie-whole-cliaracter-of-tlie-highly-compouncl-leaf-was-that-of-a-fern-froiul-whice-lias-proved-to-be-identical-with-the-type-sphenopterishiiinghausi-well-known-in-the-f-image237938604.htmlRMRR3138–. Actes du IIIme Congrès international de botanique, pub. au nom de la commission d'organisation du Congrès. Botany. 285. Fig. 7. Lyginodendron oldhamium. Double leaf-tivoce bundle and adjacent tissues in transverse section, .v centripetal ; .r' centrifngal xylem; px proto- xylem; ph phloem of bimdles; //;'- part of pliloem of stèle; ss secretory sacs; pd part of periderm. x abont 40. Welliamson Colin 1884. (Fig. 9), anrt tlie whole cliaracter of tlie highly compouncl leaf was that of a Fern- froiul, whice lias proved to be identical with the type Sphenopteris^Hôiiinghausi. well known in the f
Recueil des travaux botaniques néerlandais . ne, two or three. Thisis the common number. This is considerably less than themaximum found m B. lunaria, where Poirault (25) countedseven proto-xylems. The vascular bundle in a diarch root couldbe traced in a continuons séries of sections. In the youngestpart, the xylem is pronouncedly exarch and consists of severalreticular or spiral tracheids, before either endodermis or phloemappear. At an older stage (Fig. 29) the two proto-phloems 359 appear, thick-walled cells, alternating with the xylems. Distinctsieve tubes, even in the older stages, could Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/recueil-des-travaux-botaniques-nerlandais-ne-two-or-three-thisis-the-common-number-this-is-considerably-less-than-themaximum-found-m-b-lunaria-where-poirault-25-countedseven-proto-xylems-the-vascular-bundle-in-a-diarch-root-couldbe-traced-in-a-continuons-sries-of-sections-in-the-youngestpart-the-xylem-is-pronouncedly-exarch-and-consists-of-severalreticular-or-spiral-tracheids-before-either-endodermis-or-phloemappear-at-an-older-stage-fig-29-the-two-proto-phloems-359-appear-thick-walled-cells-alternating-with-the-xylems-distinctsieve-tubes-even-in-the-older-stages-could-image338136005.htmlRM2AJ3BWW–Recueil des travaux botaniques néerlandais . ne, two or three. Thisis the common number. This is considerably less than themaximum found m B. lunaria, where Poirault (25) countedseven proto-xylems. The vascular bundle in a diarch root couldbe traced in a continuons séries of sections. In the youngestpart, the xylem is pronouncedly exarch and consists of severalreticular or spiral tracheids, before either endodermis or phloemappear. At an older stage (Fig. 29) the two proto-phloems 359 appear, thick-walled cells, alternating with the xylems. Distinctsieve tubes, even in the older stages, could
![. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 311 to a type of stele consisting of a central core of xylem surrounded by phloem, pericycle, and endodermis. While admitting that steles of this type may sometimes be the result of the modifica- tion of less simple forms, we may confidently regard the protostele as representing the most primitive form of vascular system. The genus Lygodium affords an example of a proto- stelic fern; a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered per Stock Photo](https://c8.alamy.com/comp/RDBBME/fossil-plants-for-students-of-botany-and-geology-paleobotany-xx-recent-ferns-311-to-a-type-of-stele-consisting-of-a-central-core-of-xylem-surrounded-by-phloem-pericycle-and-endodermis-while-admitting-that-steles-of-this-type-may-sometimes-be-the-result-of-the-modifica-tion-of-less-simple-forms-we-may-confidently-regard-the-protostele-as-representing-the-most-primitive-form-of-vascular-system-the-genus-lygodium-affords-an-example-of-a-proto-stelic-fern-a-solid-column-of-xylem-tracheae-and-parenchyma-is-completely-encircled-by-a-cylinder-of-phloem-succeeded-by-a-multi-layered-per-RDBBME.jpg ". Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 311 to a type of stele consisting of a central core of xylem surrounded by phloem, pericycle, and endodermis. While admitting that steles of this type may sometimes be the result of the modifica- tion of less simple forms, we may confidently regard the protostele as representing the most primitive form of vascular system. The genus Lygodium affords an example of a proto- stelic fern; a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered per Stock Photo")
. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 311 to a type of stele consisting of a central core of xylem surrounded by phloem, pericycle, and endodermis. While admitting that steles of this type may sometimes be the result of the modifica- tion of less simple forms, we may confidently regard the protostele as representing the most primitive form of vascular system. The genus Lygodium affords an example of a proto- stelic fern; a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered per Stock Photohttps://www.alamy.com/licenses-and-pricing/?v=1https://www.alamy.com/fossil-plants-for-students-of-botany-and-geology-paleobotany-xx-recent-ferns-311-to-a-type-of-stele-consisting-of-a-central-core-of-xylem-surrounded-by-phloem-pericycle-and-endodermis-while-admitting-that-steles-of-this-type-may-sometimes-be-the-result-of-the-modifica-tion-of-less-simple-forms-we-may-confidently-regard-the-protostele-as-representing-the-most-primitive-form-of-vascular-system-the-genus-lygodium-affords-an-example-of-a-proto-stelic-fern-a-solid-column-of-xylem-tracheae-and-parenchyma-is-completely-encircled-by-a-cylinder-of-phloem-succeeded-by-a-multi-layered-per-image231975982.htmlRMRDBBME–. Fossil plants : for students of botany and geology . Paleobotany. XX] RECENT FERNS 311 to a type of stele consisting of a central core of xylem surrounded by phloem, pericycle, and endodermis. While admitting that steles of this type may sometimes be the result of the modifica- tion of less simple forms, we may confidently regard the protostele as representing the most primitive form of vascular system. The genus Lygodium affords an example of a proto- stelic fern; a solid column of xylem tracheae and parenchyma is completely encircled by a cylinder of phloem succeeded by a multi-layered per
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