THE ANGIOSPERMAE 



1565 



Fig. 1426. — Prnbnscidea fragrans (Pedaliaceae). 

 The " Mule Grab ", with long recurved 

 hooks. South Africa. 



skin or into the mouth of the animal, penetrating sometimes deeply into the 



body and causing death. 



One family which is signalized by its hooked fruits, found in almost 



all the genera, is the Pedaliaceae, 



in which the hooks reach their 



most formidable development. In 



PedaUiim there are five on each 



fruit, small but strong and acting 



like the spines of Tribiilus. In 



Sesamiim the two carpels end in 



two sharp points, developed from 



the stvles, and in Martynia these 



have become very large, woody 



hooks, while in Proboscidea they 



are lengthened to several inches, 



exceeding the length of the capsule 



and curved and pointed like fish- 

 hooks (Fig. 1426). The fruit lies 



on the ground with these horns 



upwards and if an animal steps 



on it the fruit tips up and the 



horns clasp the fetlock. It is almost 



impossible for the animal to scrape it off and it works its way upwards 



as the animal walks. Sheep on trek, or deer, may carry the fruits along 



with them for great distances, dropping seeds as they go. In Harpagophytum 



there is a different develop- 

 ment (Fig. 1427). Here the 

 flat fruit has four wings 

 which are modified into an 

 armoury of claws each about 

 an inch long and provided 

 with numerous strong 

 hooks, which attach them- 

 selves irremovably to any 

 part of an animal which is 

 unfortunate enough to touch 

 them. It is a South African 

 plant, like Proboscidea, and 

 like it is a curse of stock 

 animals. 



There are three points 

 of general importance which 

 may be noted in connec- 

 tion with the numerous devices of adherence to animals. The first is that 



in their simplest forms some of them seem to have been directed to 



adherence to the soil rather than to animals. The second is that another 



Fig. 1427. — Harpagophytum prostratiim. Fruit with 

 hooks. S. Atrica. See in text. 



