76 
SEED DISPERSAL. 
of some species of Avens with knobs, or shoes, for another 
purpose, to benefit the plants without reference to the 
likes or dislikes of animals. 
48. Diversity of devices in the rose family for seed sow- 
ing. — All botanists now recognize plants as belonging to 
separate families, the plants of each family having many 
points of structure in common. Among these families of 
higher plants, over two hundred in number, is one known 
as the rose family. Notwithstanding their close relation- 
ship, the modes of seed dispersion are varied. The seeds 
of plums and cherries and hawthorns are surrounded by a 
hard pit, or stone, which protects the seeds, while animals 
eat the fleshy portion of the fruit. When ripe, raspberries 
leave the dry receptacle and look like miniature thimbles, 
while the blackberry is fleshy throughout. The dry, seed- 
like fruits of the strawberry are carried by birds that relish 
the red, fleshy, juicy apex of the flower stalk. 
Each little fruit of some kinds of Avens has a hook at 
the apex, while in' Agrimony many hooks grow on the out- 
side of the calyx and aid in carrying the two or three seeds 
within. Plants of some other families illustrate the great 
diversity of modes of dispersion as well as the roses. 
49. Grouse, fox, and dog carry burs. — To the feathers 
of a ruffed grouse killed in the molting stage, early 
in September, were attached fifty or more nutlets of 
Echinospermum Virginicum Lehm. 
A student tells of a tame fox kept near his home, on 
the tail of which were large numbers of sand burs, and a 
