242 



Cousinia. 



Many Transcaspian species belong to this genus, most 

 of them perennials. They are all rather broad-leaved, thorny, 

 and frequently "cobweb-haired". C. annua and C. dichotoma 

 were examined as examples of annual species. The former 

 I found flowering in the sand-desert during the hottest time 

 of summer. It was about half a metre high and had broad 

 spiny leaves the axils of which bore rich dense inflorescences. 

 The plant is glabrous, the stem snow-white and glossy. 



The leaf is somewhat dorsiventral with two layers of 

 palisade cells on the upper side and one on the lower, and 

 a rather loose spongy paranchyma. The veins have bast- 

 strands, the larger ones projecting as ridges on the lower face. 



They lie several together, quite 

 separate or connected by a trans- 

 lucent aqueous tissue which merges 

 outwards into a collenchymatous 

 tissue. 



The epidermis is rather thin- 

 walled and has stomata on both 

 sides, slightly sunk. 



The stem is without green 

 Fig. 65. Cousima annua Epi- tig and has fl thick epidermis 



dermis and collenchyma of stem. 



(X 203). over a deep thick-walled collen- 



chyma (fig. 65) all the way round. 



Cousinia dichotoma is a smaller plant which may still 

 be found flowering at the beginning of July, but it begins 

 to wither about this time. The broad, spiny leaves still 

 preserve their form and position because well-provided with 

 sclerenchyma ; they are somewhat dorsiventral and have 

 stomata (not sunk)\>n both faces as in C. annua. 



Frankenia pulverulenta L. 



A slender plant with decumbent branches. Like F. 

 hirsuta (see p. 222) it occurs most frequently on somewhat 

 moist soil. The leaves are small and flat with salt-crystals 

 on both faces; the glands which are figured by SOLEREDER 



