294 



BOTANY OF THE LIVING PLANT 



becomes concave and pulpy, while the achenes produced by the 



numerous flowers are contained within it (Fig. 242). Lastly, the 

 _ perianth may be persistent, as it is in 



each of the aggregated flowers of the 

 Mulberry, and becoming pulpy they 

 embed the true fruits, which are 

 achenes (Fig. 243). It is needless to 

 multiply instances. Those quoted 

 suffice to show how various are the 

 parts that offer attractions by their 

 succulent development to fruit-eating 

 animals. Colour, scent, flavour and 

 organic content, all attract them to 

 these fruits as food. In the haste of 

 feeding they do not exclude, but bolt 

 the seeds, which may thus be carried 

 by them internally to a distance before 

 being voided with their excreta. 



In these cases the animal is an un- 

 witting agent. Another method, less 

 effective but still to be reckoned with, 

 is by means of intentional transfer of 



fruits or seeds for the animal's own purposes. Squirrels, some birds, 



and ants hoard stores of food in the form of nuts, etc. ; sometimes 



the store is not fully exhausted, so that the live seeds germinate apart 



from the parent plant. But more exact results 



come where masses of esculent tissue, often contain- 

 ing oil, occur on the surface of the seed, in the form 



of caruncles, as in the Violaceae, Euphorbiaceae 



(Fig. 421 vii.-viii.. Appendix A, p. 516), and Legu- 



minosae. Observations have been made on the 



actual transfer of the seeds of Gorse by ants, and 



the spread of that plant on certain moor-lands can 



be definitely ascribed to this agency. 



Lastly, man himself is the most potent agent in 



the distribution of plants, though his influence is as 



often destructive as constructive. He consciously 



introduces plants of economic value to new areas, 



and clears off the native flora to make way for their 



cultivation. But he also unconsciously carries with him the seeds of 



certain plants, which appear as " weeds " wherever he goes. Tlie 



Fig. 242. 

 Succulent hollowed axis of the inflores- 

 cence of the Fig, bearing achenes Avithin. 

 (After Figuier.) 



Fig. 243. 

 A "Mulberry " com- 

 posed of many flowers, 

 whose succulent peri- 

 anths enclose each a 

 dry achene. (After 

 Figuier.) * 



