DISPERSAL BY ANIMALS. 



o75 



sever themselves from the stemc, ^h.^ ^u • , ^ ee ng. 4^« ) the fruits do not 



the e... plane . ....^tZ: ^^^^ ^ ;™ - a..., ,, 



when a fating plant of SeU^ria .erUoüUuI^. ^^ZtXZZZ: Vf 

 or some other animal. The fruits of rt,;= r ^ ^ ''"^^er birds 



and surrounded by involucral Wtkl f .T "V™PPed in a™kss glumes 

 477 "and 477-) WheTthe br^" /.T . "'* ^'^ *^^P "^-'''^ <^- %- 



spi.e,butofte„ipTrf'2tl^:trL'i:;:tr"r''^^^ 



entire plant is uprooted and taken off Sul f f v ^' *"''™'' *'''' 



troublesome to the animal and atl . f *""' appendages are very 



this is achieved wit^rtr eat d ffif^ltv b ^^ "f""'"^- '" ""^ »*°- 

 or by using the fee, snouTor b a^ fth'e: mTyt TT^'' '''' "''''''■ 

 Sometimes, however, the sharp elaws and IZJlJt^'^Z^ ^bedt 



Fi6. 480. -iiuits witn needle-like spines. 



'J- ribuliis onentahs. 



or entangled in the hair or teathe.. that their extrication is attended with much 

 difhculty and suffering. 



.. ^ Tf of fruit-dispersion involving still gi^eater pain to animals is that which is 

 sTZ .^ means of straight, smooth prickles projecting from the fruit, and so 



situated as eiti.er to bore mto the foot of any animal that treads upon it, or to stick 

 into the coat of one that merely brushes by. Two groups of these fruits may be distin- 

 guished. The first group comprises those which lie loose upon the ground when they 

 are ripe To it belong Acicarpha, Ceratocarpus, Salsola, and Spinacia, in which the 

 tips ot the fruiting calyx harden and are transformed into spines standing straioht 

 up, and also Bogema, Pedalium, and Trihulus (see figs. 480 ^ and 480 2) in wliich 

 the spines project from the fruit-walls. One of the species of the last-named genus 

 VIZ., Irihulus orientalis, is of common occurrence in the lowlands of Hungary and 

 IS an object of dread to the shepherds of that region. The fallen segments ' into 

 which the fruit resolves itself are armed with hard, sharp, comparatively lone 

 spines, and are often so covered with drifted sand that only the tips of the spines 

 project above the surface (see fig. 480 2). These prickles pierce deep into the hoofs 

 and soles of animals that tread upon them, and are broken off the fruit by the 

 efforts of the latter to rid themselves of the impediment. They are thus left sticking 

 m the skin, and cause very painful, festering wounds. As examples of the second 

 group of fruits furnished with sharp prickles as instruments of dissemination we 



