Nov. 1, 1867.] 



HARDWICKE'S SCIENCE-GO SSI P. 



251 



extraordinary development, and there is also a 

 lamina formed alor.g the back of the nerve, these 





Fig. 259. Areolation of Bryum Fig. 260. Areolation of 

 ctespiticium. Hypnum rutabulum. 



additional parts being named the apical and dorsal 

 laminae (fig. 261). 



Fig-. 261. Leaf of Fissidens taxifolius. 



The Reproductive Organs. — It is now satisfactorily 

 determined that these are of two kinds, male and 

 female, and unless they occur near each other, the 

 fruit is not produced ; as an instance, I may refer 

 to Eissidens grandifrons, of which male plants only 

 have been found in Europe, female only in America, 

 hence the fruit is uuknown. 



Hedwig was the first who pointed out the nature 

 of these minute organs, but his views were long 

 opposed, for Roth and Meese asserted that when 

 sown, they produced young plants, and hence were 

 gemmae or buds. 



As in flowering plants, we find the sexual organs 

 present three modes of arrangement, and the species 

 may be — 



Synoicous — when male and female organs are 

 combined. 



IMonoicous— when they are separate, but on the 

 same plant. 



Dioicous — when separate, and on different plants. 



The male or barren flowers are either terminal 

 or lateral, and consist of an involucre of minute 

 leaves termed the perigonium; these perigonial 

 leaves vary in number, and in form and texture 

 differ considerably from those of the stem, becoming 

 gradually thinner and more delicate toward the 

 centre. Some mosses have no perigone, but the 

 male organs nestle in the axils of the stem leaves ; 

 in others the flower terminates the stem as a 

 beautiful disc or rosette, well seen in the coloured 



heads of Polytrichum ; and again it may be gem- 

 miform, or like a minute bud composed of a few 

 imbricated leaves, as in Hypnum. 



Enclosed by the perigone are the antheridia, 

 organs analogous to the stamens of flowering plants; 

 these vary in number, are somewhat sausage-shaped, 

 and usually intermixed with them are numerous 

 jointed threads termed paraphyses, whose use no 

 doubt, by the mucus they contain, is to keep moist 

 and preserve the vitality of the antheridia, for in the 

 open discoid flower they are most numerous, but in 

 the closed gemmiform flower few or none (fig. 262). 

 The antheridial sac contains the Spermatozoids, 

 minute clavato-filiform bodies with two cilia, and 

 coiled spirally, which on the rupture of the antheri- 

 dium move about with great activity; they are 

 most readily seen in the Polytricha (fig. 263). 



Fig. 262. Two Antheridia and Paraphyses of Polytrichum. 



The female or fertile flower, in a similar way, 

 consists of leaves forming a perigynium, which 

 enclose the archegonia, corresponding to the pistils 

 of flowering plants ; and so the oval base of an 

 archegonium is named the germen, enclosing in its 

 centre the germinal cell, and the tapering upper 

 part the stylidium (fig. 261). 



M 



Fig. 26a. 

 Spermatozoids. 



Fig. 264. Three Archegonia and 

 Paraphyses of Bryum. 



The inner leaves of the peryginium, as the fruit 

 forms, become enlarged into a sheath round the 

 base of the fruit stalk, forming what is called the 

 perichaetium, which is very distinct in Hypnaceae. 



Of the archegonia in each flower, seldom more 

 than one is fertilized ; sometimes, however, four or 

 five may be, and we have as] many fruits enclosed 

 in one perichaetium in Mnium uudulatum and 

 Dicranum majus. 



