. Studies on the vegetation of the Transcaspian lowlands. Botany. — 255 — have long triangular and hairy leaves, the upper ones sub- tending the solitary flowers. H. inllosa and macranthera, probably also H. pilosa, have leaves constructed after the ordinary centric type. Since the leaf is thick the aqueous tissue in the middle is large; the midrib has a bast-sheath; the hairs consist of a basal cell and a long fllamentous cell; the stomata are not sunk. The leaves of H. Karelini (fig. 78), a bracteole-succulent, are similar in structure; they have very short hairs and the stomata are slightly

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Image ID: RDRD87
. Studies on the vegetation of the Transcaspian lowlands. Botany. — 255 — have long triangular and hairy leaves, the upper ones sub- tending the solitary flowers. H. inllosa and macranthera, probably also H. pilosa, have leaves constructed after the ordinary centric type. Since the leaf is thick the aqueous tissue in the middle is large; the midrib has a bast-sheath; the hairs consist of a basal cell and a long fllamentous cell; the stomata are not sunk. The leaves of H. Karelini (fig. 78), a bracteole-succulent, are similar in structure; they have very short hairs and the stomata are slightly sunk. Closely related to the long-leaved species of Halimocnemis both in ap- pearance and inner structure we have Halanthium gamocarpum, and probably also Piptoptera turkestana, the anatomy of which I have not examined. Fig. 78. Branch of Hali- mocnemis Karelini. July. Suaeda. (Nat. size). The leaves of a number of species of this genus have been examined. As regards leaf-structure these may be divided into three groups. The leaf-structure of the species of the first group is similar to that already described for S. maritima (see for instance Warming 1897, p. 207, 1890, p. 221). Below the thin-walled epidermis there is a green mesophyll of palisade- like cells which become larger and contain less chlorophyll towards the interior; the veins lie in a curve in the middle of the leaf. Other species belonging to this group are: S. setigera and S. Olufsenii (from Pamir), also S. linifolia which differs in having flat leaves with ordinary isolateral green- tissue. The second group of Suaeda has underneath the epid- ermis a single layer of palisade cells all round and a starch- sheath below this (fig. 79, B). Thus far these leaves follow the ordinary centric type of the Chenopodiaceae. But those veins, which in other organs of this type run obliquely through the central aqueous tissue and arrange themselves. Please note that these images are extracted from scanned page images that

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