— 178 — 



fruit, probably they are burned by the heat of summer. 

 The fruit is a crescent-shaped, one-seeded, woolly-haired pod 

 about 1 centimetre in length and easily transported by the 

 wind (see fig. 23). 



The anatomical structure of the assimilation- shoots and 

 the year-shoots is very similar, but the former have no 

 cambium; Fig. 26 shows the inner structure. There are 8 or 

 9 grooves within which the palisade tissue lies in V-shaped 

 tracts bounded towards the interior by a row of storage-cells. 

 At the apex of each ridge there is a mass of collenchyma 

 and deeper-seated is a band of sclerenchyma of which another 

 band is found outside each vascular bundle. Stomata only 

 occur in the grooves, they are slightly sunk and hidden by 

 scale-hairs. 



Calligonum Caput Medusae Schrenk. 



A shrub or small tree, 1 to about 3.5 metres high and 

 leafless. Its home is the sand-desert and it is extensively 

 utilised in the plantations along the railway; 90 p. cent, of 

 the cuttings strike root, and yeai'-old plants from the nurseries 

 always transplant successfully. Comparatively speaking the 

 plant is distinctly green, but in this respect it is far behind 

 the Salsola species. 



The year -shoots are long (about 40 centimetres), thin 

 and jointed. The leaves are scale-like and membranous, and 

 form a sheath round the stem (Polygonaceae). All or most 

 of the leaves subtend branches, the upper ones often flowers, 

 the lower ones annual assimilation - shoots. Rindowsky 

 (1875 1. c.) drew attention to the difference in Calligonum 

 between "rami assimilationis" and "rami lignosi", see also 

 B. JoNSSON (1. c. p. 18). There is, however, no very hard 

 and fast limit between the two sorts of branches. The 

 outer part of the year-shoot dies away after the cessa- 

 tion of the vegetative-period, generally together with the 

 branches. New year-shoots arise singly or several together 

 from the leaf-bases of the old shoots, sometimes on branches 

 several j^ears old (see figures 11 and 27). Where several are 

 present together, some are generally more strongly developed 



