NEW AND RARE MOSSES FROM THE WEST OF SCOTLAND 169 



of the same size throughout base or lowest fourth, a Httle 

 shorter towards margin, gradually lessening upwards trans- 

 versely into the large chlorophyllose, sharply quadrate cells, 

 ,013-. 018, or even .02 by .01-. 014 mm.; apothecia on a 

 rather short pale seta, elliptical, or narrowly so, lid slightly 

 convex, red, prolonged into a slender yellow or reddish 

 acumen from a half to nearly the length of capsule, teeth 

 long, red, 16, barred and papillose. Propagula are seen 

 rather frequently attached to the low^er ends of leaves, ellip- 

 tical, (4-6)-septate, with 2-4 irregularly longitudinal septa, 

 chlorophyllose, then nearly hyaline, .13-. 22 by .04-. 05 5 mm. 

 There are still two, if not three, minor differences between 

 this moss and its prototype which I have not fully investi- 

 gated, to the discussion of which I may return. 



On the bark of an old apple tree in the garden of South- 

 bar house, near Renfrew, the property of Mr. R. Sutherland, 

 to whom I have dedicated this moss ; near New Galloway, 

 by Mr. J. M'Andrew ; detected in one of my more recent 

 collections from Ben Lawers. 



As my experience of the nature of mosses increases, I 

 am becoming more strongly impressed to the effect that 

 there is an alternation of generation between these propagula 

 and spores, that the propagation of spores implies a greater 

 vital energy on the part of the plant to produce them, and 

 that accordingly it becomes necessary at certain intervals for 

 such an alternation to occur in order to restore the balance 

 of energy, and that during this stage of comparative quiescence 

 these propagula are produced, and serve the purpose not only 

 of allowing this quiescence to continue, but to increase the 

 vegetative powers of the plant by generating new and im- 

 proved individuals. Besides, I am becoming of the opinion 

 that differences in the common areolation of the leaf, such as 

 are indicated above, serve the purpose, intei' alia, of diverting 

 this energy in new directions, so as to produce, by means of 

 these propagula, variations in type, and ultimately to serve 

 the purpose of producing new varieties, as well as of giving 

 new types, a proportion of which become permanent. My 

 thoughts in this direction have been strengthened by observing 

 that Ulota phyllantha, which has hitherto been almost entirely 



