— 226 — 
are spread out or reflexed. In spring and early summer the 
plant developes leaves (see fig. 52) which are linear-lanceolate, 
2—3 centimetres long, and white-haired, but the leaves fall 
off later in the summer so that the branches become the 
only assimilating organs. In late summer the larger plants 
are leafless, globular and spiny shrubs. The spines are 
formed by the year-shoot branches of secondary and tertiary 
Fig. 53. Convolvulus erinaceus. A, Transverse section of the green cortex 
and part of the wood; two vessels are represented; c, Cambium; 1, Secreting 
cell. B, Stoma. C, Epidermis with hairs, seen from above. D, A similar 
view of Convolvulus fruticosus. (X 203). 
order, and also by the uppermost ones of primary order 
which as a rule have formed only one internode and the 
beginning of a second one when growth ceases, hence the 
branch remains as a spine, terminated by a dead, withered 
point. 
The white flowers occur singly on these small branches, 
and open in June and July. AITCHISON says that they open 
at sunrise, but I have found them open in the middle of the 
day in a broiling sun. 
