326 SOME SPECIAL ADAPTATIONS 
with the seeds, the latter passing through the body un- 
harmed (strawberries, grapes, and most berries). Many 
small, rounded seeds dropping to the earth are widely 
distributed by animals to whose feet the earth containing 
them clings, thus being carried long distances. Such are 
the majority of the common weeds of the roadsides, 
barnyards, and waste places (pigweeds, lamb’s quarters, 
purslane, knot-grass, etc.). Of special interest, but rela- 
tively infrequent, are the plants that have fruits that 
dehisce explosively so that their seeds are flung compara- - 
tively long distances, thus placing them where they do 
not compete with their parents (Oxalis, touch-me-not, 
various vetches, wild geranium, etc.). 
REFERENCE BOOKS 
W. F. Ganone, The Living Plant, New York, 1913. 
F. E. Ciements, Plant Physiology and Ecology, New York, 
1907. 
H. C. Cowtszs, Ecology (in Textbook of Botany by Coulter, 
Barnes and Cowles) Chicago, 1911. 
HerMANN MULLER, The Fertilization of Flowers, Engl. Ed., 
London, 1883. 
Paut Knuru, Handbook of Flower Pollination, Engl. Ed. 
Oxford, 1906-9. 
Ena. WaArMING, Oecology of Plants, Engl. Ed., Oxford, 1909. 
