280 SELECTED NOTES. 



When in a growing state, the operculum fits over the peri- 

 stome very closely, and in the specimen under observation the 

 impress of the teeth on its inner surface may be very plainly seen. 

 Detached opercula are shown at h and /. 



Examination of the entire fructification of P, piliferum proves 

 that the calyptra would seem to perform the part of a very 

 serviceable overcoat. These highly developed calyptra (Figs. 2 

 and 5) present a very different appearance from the calyptra of 

 Atrichum imdulatu7)i {c, Fig. i), but by careful examination it 

 may be seen that the specimen, though membranous, is not 

 entirely devoid of the woolly arrangement, as is evidenced by the 

 spinulose fibres at the apex. When all is ready for the liberation 

 of the spores, the epiphragm (which originally closed up by 

 means of fistular processes, or mammae in some species, the inter- 

 stices of the peristome) now becomes shrivelled, and the spores 

 escape between the teeth of the peristome. 



I have selected this moss for a detailed description as it is one 

 of the most beautiful as well as one of the most common mosses 

 we have, and is generally one of the first to attract the attention 

 of the rising biologist. I give a Hst of the synonyms by which 

 this moss is known. 



Atrichinn undu/atum, Linn. Catharinea Ehrharti. 



Bryiim phyllitidis. M7iium Jindulatum. 



B. phyllitidy solium, Polytrichiun undulatum, 



B. undulatum. Callibryiwi polytrichoides. 



Catharinea callibryon. Callibryum U7idulatu7n. 



Catharinea undulata. Oligotrichiwi undulatum. 



It must not be supposed the fructification of all mosses are 

 constructed on lines corresponding with the degree of develop- 

 ment exhibited in Atrichum. Here we have thirty-two teeth 

 (these teeth are always in number a multiple of four). The 

 members of the tribe Georgiacece are characterised by having only 

 four teeth (see Fig. 4). Those of the tribe Andreacaccce have no 

 peristome at all, but the capsule itself dehisces longitudinally, 

 forming four to six slits, through which the spores escape, as in 

 Fig. 5. In some cases the spores are set free simply through the 

 decay of the capsule, as in Archidiuni ailer?iifo/ium, nature pro- 

 viding no other method of liberating them (see Fig. 6). 



