Seeds and Their Germination. 



25 



that seeds which come up with their coats on do not thrive. 

 The seed at b in the fignre on page 24 was first planted the 

 other side up. It was turned 

 over when the knob on the 

 right had begun to open the 

 seed. The caulicle, which 

 then pointed directly up- 

 ward, gradually straight- 

 ened, bent downward, and 

 finally the second knob 

 grew, by the help of which 

 the seed leaves were in a 

 fair way to get out when 

 the drawing was made. 

 Some native California 

 plants get out of their coats 

 in a similar manner.* 



Peculiar Germination 

 of the seeds of some plants 

 of the Pacific Slope. The 

 seeds of Big-root a pest 

 which grows in nearly every 

 field behave in a remark- 

 able manner. The nut-like seeds drop from their prickly 

 pods in June or July, and soon become covered with leaves. 

 The rains of November and December cause them to sprout, 



*It would be a good experiment to plant ten squash seeds with the flat sides 

 horizontal, just as they would naturally fall, and ten seeds with the sharp ends 

 down. The last would seem the better way, because the caulicles would be point- 

 ing downward. The results of such an experiment are very interesting. 



Fig. 20. Germination of Big-root, a. Planted 

 in a flower pot, the growing petioles forced the 

 cotyledons and feed coat above the surface (S) 

 of the toil. b. Planted in a shallow box, the 

 growth was lateral, c. Natural growth when 

 lying on the ground, d. Germinating seed, 

 natural size, pushing the small caulicle (below 

 /) into the } round. The plumule is seen in the 

 DOttom of the petiole tube at f. e. Hairs which 

 attach to the soilat the surface. 



