255 



have long triangular and hairy leaves, the upper ones sub- 

 tending the solitary flowers. 



H. villosa 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 filamentous 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 Piptoplera 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 



