182 



trary a thick-walled hypodermnl layer, and only one palisade 

 layer. 



With Calligonum Caput Medusae are related the other 

 species of this genus which grow in Transcaspia, see the 

 plant-list p. 154. BORSZCZOW has described many species; 

 as to the systematic value of these I have no definite views. 

 Variations are especially common in the fruits, but there is 

 also considerable variety in height and in usefulness as 

 sheltering plants. PALEZKIJ states that most of the species 

 have a tendency to lose their branches in summer, a result 

 of the heat of the sun. This shows itself first as rust- 

 coloured spots which gradually make their way through the 

 branches. Calligonum eriopodum is the species which suffers 

 least from this injury, it is also of high stature and being 

 hardy in several respects it is more extensively used in 

 planting shelter -belts than the other species. Calligonum 

 arborescens is also employed on account of its size, it is 

 said to attain a height of 6 metres. 



Calligonum plants are raised in the nursery; one-year- 

 old specimens are about one metre high. They can only 

 endure water as seedlings during the cotyledonary stage. 



Under natural wild conditions Calligonum Caput Medusae 

 and C. Pallasii (= Pterococcus aphyllus) seem to be the most 

 common. The fruits of the latter have eight broad wings 

 instead of tufts of setae (fig. 28 C). All the species have thin 

 assimilation-branches. 



Ephedra alata Dene. ( E. slrobilacea Bge.). 



I have seen this plant in the sand-desert as a shrub 

 one foot high, but it is said to become much higher. Part 

 of a stem I saw was 14 centimetres in circumference. 



The leaves are membranous and sit three and three 

 together at the joints. The year-shoots may grow long, they 

 are placed laterally on the previous year- shoot, and arise 

 one, two or three together. Some nodes may for several 

 successive years be the starting point of new branches which 

 thus form bunches. My notes include no other observations 

 on the shoot- structure. 



