484 



HUTCHINSON'S POPULAR BOTANY 



wild horses that roam the plains of South America"; and certainly one 

 of the objects of the hooked spines and bristles of fruits of whatever kind 



is their dispersion by animals. 

 Kerner estimates that the 

 fruits and seeds of about 10 

 per cent, of all Flowering 

 Plants are provided with pro- 

 cesses of this description, 

 some of which take the form 

 of hooks and others of barbs. 

 In this case the Mariynia 

 fruit splits to release the con- 

 tained seeds which are gradu- 

 ally shaken out by the effort 

 of the animal to get rid of its 

 encumbrance. The Goose- 

 grass (Galium aparine), a 

 long, weak, straggling plant 

 very common in our hedges 

 and thickets, has small fruits 

 (dry, indehiscent pericarps, 

 in this case) which are liter- 

 ally covered with hooked bris- 

 tles. Country people call the 

 plant " cleavers," from its 

 habit of cleaving to objects 

 with which it is brought in 

 contact, and children like to 

 throw the hispid fruits at one 

 another for the fun of seeing 

 them " stick." In the Bur- 

 weed (Xanthium, fig. 604) the 

 hooks are borne upon the 

 hardened involucre, which 

 grows about and covers the 

 one-seeded fruit. Very simi- 

 lar in effect are the top- 

 shaped fruits of Agrimony 

 (Agrimonia eupatoria), which 

 become detached from the 

 plant by every fur-clad crea- 

 ture that touches it in pass- 

 ing. A walk through the pastures in early autumn will result in our 

 nether garments being thickly coated with these fruits. 



FIG. 599. EARTH-NUT (Arachis hypogcca). 



The young pods are thrust into the eartli by the lengthening of th 

 stalks, and there they ripen their seeds. 



