134 MUSCINEJE 



Muscineae is indicated by the position of the sexual organs on the' 

 vegetative shoots ; as these organs approach nearer and nearer to the 

 apex, the shoot gradually loses its vegetative character, and becomes 

 differentiated into a special fertile branch. 



The sexual organs are frequently surrounded by crowded and slightly 

 modified foliar structures, the whole arrangement having then some 

 resemblance to the flower of Phanerogams. Thus, in the thalloid 

 forms, the antherids and archegones are commonly borne on umbrella^ 

 shaped outgrowths of the thallus which are not inaptly termed respec- 

 tively male and female inflorescences. In the foliose forms they are 

 frequently arranged at the extremities or laterally on branches, and 

 closely surrounded by small leaves constituting the perichcBte or perianth, 

 reminding one of the bracts, or even of the calyx, of Flowering Plants, 

 the whole structure forming an hermaphrodite, monoecious, or dioecious 

 ' flower.' They are often accompanied by barren, hair-like cells, termed 

 paraphyses. 



The first result of the impregnation of the oosphere by an anthero- 

 zoid is the formation of an ovoid embryo by repeated cell-divisions ; 

 this continues to grow at its apex, and finally develops into the 

 fructification here known distinctively as the sporogone, the ultimate 

 form of which varies greatly in the different families. In its most 

 perfect form the sporogone is differe^iated externally into a slender 

 stalk or seta, which penetrates into the base of the archegone, or even 

 into the underlying tissue, and a spore-capsule, called indifferently the 

 sporange, theca, or urn. Along with the spores the spore-capsule some- 

 times contains (in the Hepaticas) elongated cells thickened by a single 

 or double spiral band known as elaters, which assist in the dissemination 

 of the spores. The mature sporange is, in the highest forms, sur- 

 mounted by a cap or calypter, which becomes completely detached at 

 its base, while the mature lower portion of the archegone encloses the 

 base of the seta in the form of a sheath or vagine ; in the lower forms 

 the spore-capsule always remains enclosed in the calypter. The spores 

 of the Muscineae are always formed in fours within the spore-mother- 

 cells, which latter are produced within the cavity of the sporange by free 

 cell-formation, from a special layer or layers of cells known as the 

 archespore. When ripe they have a double cell-wall, the outermost 

 layer or exospore being provided with small excrescences, and the inner 

 layer or endospore bursting through it on germination. The contents 

 consist of protoplasm, chlorophyll-grains, starch, and oil. 



The thalloid or leafy plant (as the case may be) does not, as a rule, 

 arise immediately from the germinating spore, but, in all the higher 

 forms, only after the previous formation of a colourless confervoid or 



