LITHOSPEEMUM PUEPUREO-CCERULEUM. 
129 
Only half of the twelve to eighteen flowers upon each cyme 
produce fruit : one or at most two polished porcelain-like nuts 
being found in each fruiting calyx. These nuts are very per- 
sistent and conspicuous on the brown, withered, but erect stems ; 
which when seen the next spring suggest the idea of deserted 
telegraph poles with unusually lai-ge insulators ; but on being 
handled in preparation for the herbarium they detach easily, and 
can hardly be preserved in situ. Meanwhile the barren stems, 
which are not usually produced from a flowering root (I find that 
the root appears to produce alternately barren stems and fertile 
ones, and seldom both in the same season), have also developed, 
and from their first erect position have loftily arched until in the 
autumn their tips reach the ground. The terminal portions 
have already put forth some short stout rootlets, and when these 
touch the earth they soon take hold, and new plants result. At 
spots where the Lithospermum is abundant, the ground in 
October is thickly set with green hoops, about the size and shape 
of those used in Croquet ; although in shade a barren stem will 
occasionally form an arc with a chord of three feet. As soon as 
the rooting tip has established itself, the rest of the shoot 
becomes brittle and decays, as if its vitality had been expended 
in the formation of the young plant. It will be interesting to 
investigate the physiological cause of this peculiarly speedy 
decay of the barren shoot after rooting. A somewhat analagous 
process takes place in the propagation of the fruticose brambles. 
It is also worthy of note that, although the mode of growth I 
have described is extremely well adapted for rapid extension over 
large tracts of ground, there exists some subtle climatic or other 
influence which restrains the plant within the narrow limits I 
have indicated. 
