The origin of floral structures through insect and other agencies .
RM2AWK0KCThe origin of floral structures through insect and other agencies .
. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. . Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Henslow, George, 1835-1925. New York : Appleton
RMPG3KPH. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. . Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Henslow, George, 1835-1925. New York : Appleton
The origin of floral structures through insect and other agencies . I THE RECEPTACULAR TUBE. 93 Roses (Fig. 24), etc., occasionally bear foliage on theexternal surface of the tube, and when the caljx of the Rose becomes abnormally folia-ceous, stipules (Fig. 24, st.)may appear at the summitof the tube, indicating that.
RM2AWK6JDThe origin of floral structures through insect and other agencies . I THE RECEPTACULAR TUBE. 93 Roses (Fig. 24), etc., occasionally bear foliage on theexternal surface of the tube, and when the caljx of the Rose becomes abnormally folia-ceous, stipules (Fig. 24, st.)may appear at the summitof the tube, indicating that.
. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. . Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Henslow, George, 1835-1925. New York : Appleton
RMPG3M3P. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. . Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Henslow, George, 1835-1925. New York : Appleton
The origin of floral structures through insect and other agencies . flowers is very various, and anyorgans can form them. It will be enough to enumerate a fewlocalities as follows: The Lime, species of MalpigMa,i andperhaps Coronilla, furnish instances, which are comparativelyrare, of the sepals of the calyx beingnectariferous. In Buttercups, Hellebore,and Aconite, nectar is secreted by thepetals or their representatives. InViolets, Atragene (Fig. 44), Fentstemon,and Stellaria the filaments undertakethe duty, while in Caltlia, Monotropa,and Ehododendron it is the carpels orpistil. In most inst
RM2AWK3AFThe origin of floral structures through insect and other agencies . flowers is very various, and anyorgans can form them. It will be enough to enumerate a fewlocalities as follows: The Lime, species of MalpigMa,i andperhaps Coronilla, furnish instances, which are comparativelyrare, of the sepals of the calyx beingnectariferous. In Buttercups, Hellebore,and Aconite, nectar is secreted by thepetals or their representatives. InViolets, Atragene (Fig. 44), Fentstemon,and Stellaria the filaments undertakethe duty, while in Caltlia, Monotropa,and Ehododendron it is the carpels orpistil. In most inst
. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. Fig. 43.—Stipules of/mpotiens; o. sertlon sbowing anatomy b, with a drop of honey in the centre (after Earner).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Henslow, George, 1835-1925. New York : Appleton
RMPG3JJT. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. Fig. 43.—Stipules of/mpotiens; o. sertlon sbowing anatomy b, with a drop of honey in the centre (after Earner).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Henslow, George, 1835-1925. New York : Appleton
The origin of floral structures through insect and other agencies . ular to the filaments, corresponding to the weight ofthe insect; while the third and upward force is that exertedby the filaments to counteract the resultant of the two former.* The origin of the adhesion between the stamens and theouter whorls is revealed by anatomical investigations; forthe rule is, as described in the case of Prunus, that the fibro-vaseular cords of the stamens arise by division from those ofthe outer whorls whenever they are superposed to them. In other words, when adhesions are seen between thefloral whor
RM2AWK8METhe origin of floral structures through insect and other agencies . ular to the filaments, corresponding to the weight ofthe insect; while the third and upward force is that exertedby the filaments to counteract the resultant of the two former.* The origin of the adhesion between the stamens and theouter whorls is revealed by anatomical investigations; forthe rule is, as described in the case of Prunus, that the fibro-vaseular cords of the stamens arise by division from those ofthe outer whorls whenever they are superposed to them. In other words, when adhesions are seen between thefloral whor
. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. 18G THE STRUCTURE OF FLOWERS. successively. If the stamens be very numerous they usually emerge in centripetal order, as in Buttercups; but they may form " centrifugal groups," as in Hypericum ; the numerous stamens of Cistus and Selianthemum, as well as of Cactus, Opuntia, and Mesemhryanthemum, and the Loasece, are also centrifugal in their development. Lastly, if the carpels form a whorl, they, too, emerge simultaneously ; but if they be numerous and spirally arranged they emerge and de
RMPG3WD1. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. 18G THE STRUCTURE OF FLOWERS. successively. If the stamens be very numerous they usually emerge in centripetal order, as in Buttercups; but they may form " centrifugal groups," as in Hypericum ; the numerous stamens of Cistus and Selianthemum, as well as of Cactus, Opuntia, and Mesemhryanthemum, and the Loasece, are also centrifugal in their development. Lastly, if the carpels form a whorl, they, too, emerge simultaneously ; but if they be numerous and spirally arranged they emerge and de
The origin of floral structures through insect and other agencies . ntact bytheir edges, the veins ramify and anastomose all over thegeneral space between the two adjacent dorsal ribs, com-pletely obliterating all trace of the line of union betweenthem. In the case of the Primrose, however, the calyx hasthe exact appearance of five pinnately nerved leaves beingunited by their thin and impoverished edges, where there isnothing but translucent tissue without any cords at all. It is important to observe this more or less completemodification of the fibro-vascular system under congenitalcohesion,
RM2AWKAFFThe origin of floral structures through insect and other agencies . ntact bytheir edges, the veins ramify and anastomose all over thegeneral space between the two adjacent dorsal ribs, com-pletely obliterating all trace of the line of union betweenthem. In the case of the Primrose, however, the calyx hasthe exact appearance of five pinnately nerved leaves beingunited by their thin and impoverished edges, where there isnothing but translucent tissue without any cords at all. It is important to observe this more or less completemodification of the fibro-vascular system under congenitalcohesion,
. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. 60 THE BTRUCT0BE Of FLOWEKS. walls whlcli touch.; so that when they are fully grown the cohesion is firmly secured. An imitative cohesion is seen in the anthers of the Heartsease, which arises from the interlocking of marginal hairs down the sides of the cells. Anthers, when thas closely approximate without actual cohesion, are usually called " connivent," as in Ericaeece, and the word is perhaps appropriate to those of Solanum Dulcamara; but in this plant the union is very close, and mig
RMPG3XEY. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. 60 THE BTRUCT0BE Of FLOWEKS. walls whlcli touch.; so that when they are fully grown the cohesion is firmly secured. An imitative cohesion is seen in the anthers of the Heartsease, which arises from the interlocking of marginal hairs down the sides of the cells. Anthers, when thas closely approximate without actual cohesion, are usually called " connivent," as in Ericaeece, and the word is perhaps appropriate to those of Solanum Dulcamara; but in this plant the union is very close, and mig
The origin of floral structures through insect and other agencies . rts of the whorls are free. Thus inThalamifone, of such an order as Ranunculacea; with regularflowers and with all the parts of the perianth whorls free, theflowers are usually visited by a much greater number andvariety of insects than are those of orders of Corolliflorce. Forexample, Miiller records sixty-two species of insects as seen byhim to visit Ranunculus acris ; whereas the humble-bee aloneenters the gamopetalous tube of the Foxglove. This adapta-tion oi form to insect visitors will be better appreciated whenwe come t
RM2AWKA7TThe origin of floral structures through insect and other agencies . rts of the whorls are free. Thus inThalamifone, of such an order as Ranunculacea; with regularflowers and with all the parts of the perianth whorls free, theflowers are usually visited by a much greater number andvariety of insects than are those of orders of Corolliflorce. Forexample, Miiller records sixty-two species of insects as seen byhim to visit Ranunculus acris ; whereas the humble-bee aloneenters the gamopetalous tube of the Foxglove. This adapta-tion oi form to insect visitors will be better appreciated whenwe come t
. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. 90 THE STJltrCTURE OF FLOWERS. Naudin, Ph. Van Tieghem, and, I think, English botanists in general.* There are three methods of investigation, â which conjointly may gnide us to the discoveiy of the real nature of the tube. The first is that of following its development; the second is teratological, and the third anatomical. Morphological Investigations.âIn tracing the morpho- logical development of flowers of the Eosacece, where the receptaeular tube is a characteristic feature, one notices how a
RMPG3KWA. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. 90 THE STJltrCTURE OF FLOWERS. Naudin, Ph. Van Tieghem, and, I think, English botanists in general.* There are three methods of investigation, â which conjointly may gnide us to the discoveiy of the real nature of the tube. The first is that of following its development; the second is teratological, and the third anatomical. Morphological Investigations.âIn tracing the morpho- logical development of flowers of the Eosacece, where the receptaeular tube is a characteristic feature, one notices how a
The origin of floral structures through insect and other agencies . Tdj, or at least is homologous with, the petiolar portion of the caljcine leaves (Fig.27). Phjllomes, however,are after all but modifiedportions of caulomes, andpetioles are still less de-partures than are bladesfrom the nature of anaxis; so that while insome cases one is inclinedto regard the tube asmore strictly axial, inothers it seem to be morehomologous with a sort offasciation of petioles. We shall see directlythat the receptacular tubeof Prumis contains thebasal portions of the cordsproper to the calyx andcorolla, so th
RM2AWK63KThe origin of floral structures through insect and other agencies . Tdj, or at least is homologous with, the petiolar portion of the caljcine leaves (Fig.27). Phjllomes, however,are after all but modifiedportions of caulomes, andpetioles are still less de-partures than are bladesfrom the nature of anaxis; so that while insome cases one is inclinedto regard the tube asmore strictly axial, inothers it seem to be morehomologous with a sort offasciation of petioles. We shall see directlythat the receptacular tubeof Prumis contains thebasal portions of the cordsproper to the calyx andcorolla, so th