ARCHEGONIUM OF MNIUM. 



347 



Mnium. The paraphyses, forming in their lower part a long 

 cell-row, usually broaden at their tip into a spathulate unilamel- 

 lar cell-surface. If a male flower of Polytrichum is squeezed 

 slightly between the fingers, the contents of the antheridia come 

 out as a milky slime, clearly visible against the reddish ground. 



The form of the antheridium of Mosses varies very little, 

 and the accompanying Fig. 125 of that of a moss especially 

 common upon shaded cinder-paths and other 

 places where the substratum has been burnt, 

 upon walls in green-houses, etc., viz., Fnnaria 

 hygronietrica, will serve to illustrate it. 



Archegonia of Mnium. The female 

 flowers of Mnium hornum, however, are not 

 nearly so recognisable as the male, and it is 

 often necessary to seek for them longer. The 

 plants bearing them are far shorter than the 

 male, and somewhat darker in foliage. The 

 upper leaves close together, after the fashion 

 of a bud, in order to protect the female sexual 

 organs, the archegonia. As is shown by 

 median longitudinal sections, the apex of the 

 flowering axis is not broadened to any extent, 

 but greatly blunted, and from this we can 

 judge when we are dealing with a female 

 flower, even if we do not happen at once to 

 rind the archegonia. The central conducting 

 bundle of the stem is somewhat swollen 

 under the receptacle, and ends, just as under 



the male flowers, in a chlorophyll-containing theridium bursting; the 



m , T.C -i i -i i f i body of the antheridium 



tissue. The modified leaves which form the .shows its wall of cells 



female perichsetium, while remaining leaf- ^^ nin f ? thfSeJo! 

 like, decrease in size towards the middle of zoids (spermatozoids) (x 

 1/1 e 1 a 350). />, the spermato- 



the flower ; the apex of the flower is occu- zoids more strongly mag- 

 pied by only a few archegonia, so that it ^ e . d '' c \^ e ^^ozoid 

 is necessary^to take strictly median sections of Polytrichum (x 800). 

 in order to disclose them. The arche- (Afte 

 gonia are constructed essentially like those of the Liverworts (see 

 Fig. 126), but the foot is far more strongly developed, only 

 tapering a little downwards, and forms the greater part of the 

 lower half of the archegonium, and hence the oosphere appears 

 comparatively small. We must look for it close under the com- 



