4^66 



INTRODUCTION TO CRTPTOGAMIC BOTANY. 



the spores ; in mosses the cells which do not produce spores 

 are abortive. The spermatozoids are produced exactly as in 

 Hepaticce, and have the same form. In phaenogams the 

 germen is produced before impregnation. It is obvious that 

 no sporangium can be produced in mosses without impregna- 

 tion, as the whole depends upon one embryonic cell. Without 

 some system of propagation by gems, many dioecious species 

 would soon die out, in consequence of the rarity of fructification. 



Fig. 99. 



a. Portion of leaf of Odohlepharum albidum, from specimens collected 

 by Cuming, seen from above. 



b. Ditto of Leucobryum glaucum, seen from the inner side, witb the 

 intermediate cells. 



c. Ditto of Sphagnum latifolmm, seen from above. 



d. Hypopterygium Smithianum, showing the distichous leaves and 

 stipules, ■with a portion of the edge of the leaf. From a Norfolk Island 

 specimen in the Hookerian Herbarium. 



e. Permanent mother-cells of Eucaniptodon perichcetialis. From a 

 specimen given me by Dr. Montague. 



f. Andnea subidata, portion of leaf from Cape of Good Hope. From 

 Hook. Herb. (The light parts, however, ought not to look like per- 

 forations.) 



g. Campylopus lamellinervis, under side of nerve. From Hook. Herb. 



All more or less magnified. 



514. The leaves of mosses, as regards at least the lamina, 

 usually (Fig. 98, (J) consist of a single stratum of homologous 

 cells as in Jungermanniw, but this is by no means constant. 



