VACATION OBSERVATIONS.— Ill 



By Francis E. Lloyd 



Behavior of the Spores in Polytrichum. — A remarkably pretty 

 demonstration of the behavior of the spores during their dis- 

 semination may be had in Polytrichum if one examines the dry 

 sporogonium after the operculum has been removed. The ob- 

 server must hold the seta between the thumb and finger of one 

 hand with the diaphragm of the capsule opposite the eye, the 

 capsule being so placed that the light shines through the dia- 

 phragm and at the same time so tilted that the dry spore mass 

 falls against it. The seta must now be gently tapped so as to 

 make the capsule vibrate, when the spores will escape between 

 the shrunken teeth of the peristome and be scattered. The point 

 of special interest here is the manner in which the spore-mass 

 rolls around in the capsule and falls, in this way and that, against 

 the diaphragm. The spores appear, in their movements, as of 

 considerable weight, an illusion caused by the extreme ease with 

 which they roll over one another. This, of course, is' due to 

 their very great dryness, and, possibly, to surface characters. 



The Color of the Spores in Polytrichum. — The writer does not 

 recall that it has been heretofore pointed out that the ripe spores 

 of Polytnchuin commune and those of P. Ohioense differ very mark- 

 edly from each other in color when seen en masse. Indeed, the 

 amount of difference is so great that the beginner would be able to 

 distinguish the species very readily. In P. commune the color is 

 yellow-green ; in P. Ohioense, brown-yellow. Corresponding dif- 

 ferences in the structure of the spores are seen on microscopic 

 examination. Those of the former are smaller, and more densely 

 filled with protoplasm, and the coloring more readily seen than in 

 those of the latter species ; the vacuole is very much larger, also, 

 in the spore of P. Ohioense. 



Destruction of Mosses by Fungi. — Apparently but very little at- 

 tention has been directed to the relations of mosses and fungi. 

 Whether any specific diseases in mosses are caused by fungi is an 

 open question. Nevertheless, under certain conditions, such as 

 prevailed during July of last year, in northern Massachusetts, 



