152 THE PLANT WORLD. 



south 14'i'"-, with one fruiting stem; another northwest 13dm. with two 

 stems, one in fruit ; the fifth took the same general direction as the 

 last and was 17'^in. long, bearing one small stem. Some of the roots 

 were branched, the branches varying in length and size. The main 

 stem was 15™™- in diameter at the base, its root lo™™- where it began 

 to branch. The main branches, which started from this point or close 

 by, were slender, averaging 1-4™'^- in diameter, the thickest parts 

 being 7*^™- 



The underground stem of the Scouring Rush {Eqiiisetuvt hyernale) 

 frequently runs a long distance in the sand. One was traced last 

 summer 25^™-, but the end was not quite reached in either direction 

 from the principal stem, as it breaks easily on account of its system 

 of joints, and it is difficult to recover the lost part when small. It 

 ran about a decimeter beneath the surface, but was a little wavy, ap- 

 proaching the surface more nearly in some places than in others. It 

 was 3-5™°^- in diameter and sent up stems at varying intervals. It is 

 easy to detect the course of the rootstock from this row of stems. It 

 is black, slightly enlarged at the joints, which have a sheath from the 

 base of which the roots spring. It is fluted like the aerial stem and 

 well provided with tubercles, but not so regularly arranged as on the 

 green stem, the hollows as well as the ridges being covered about the 

 same. 



There n^ay also be more of Gentiana piiberiila below than above 

 ground. A plant growing in the sand was dug up at the time of 

 flowering in September. The stem was 2.5^™- high; it had two roots 

 starting from the base like the prongs of a fork. They descended 

 into the soil obliquely, one for 6.5'^™-, the other S'^"'- The vertical dis- 

 tance from the end of the latter to the surface of the ground was 



Chicago, 111. 



On the 14th inst., that being the first real warm day this spring, 

 I observed on the campus of Purdue University a peculiar popping of 

 the pine cones. This popping began about 9 a. m. and continued on 

 into the night. It was so distinct that it could be heard easily at a 

 distance of fifty or sixty feet. Being curious it observe it more close- 

 ly, I climbed one of the trees and found that the popping was evi- 

 dently due to a loss of moisture and a consequent contraction, which 

 resulted in the gradual opening of the cones. This is certainly a very 

 clever ecological device, for the seeds are thus kept in shelter during 

 the winter, and when spring comes, and all nature is favorable to ger- 

 mination, the seeds are released from their coverings and find a com- 

 fortable lodging in the soil. — Claude Riddle, Purdue University, La- 

 fayette, Ind. 



