MUSCI. 



547 



vascular system. Leaves minute and imbricated (fig. 774 /), entire, 

 or serrated; sometimes with condensed cells in the form of ribs or 

 nerves. Reproductive organs of two kinds: 1. Antheridia (fig. 

 368), cylindrical or fusiform stalked bags, containing powdery matter 

 and phytozoa (fig. 368, 3), and mixed with empty jointed filaments 

 or paraphyses ('ira.^vais, an offset). 2. Urn-shaped pistillidia (fig. 

 777), enclosed at first within a calyptra (x-m^v^-r^ a covering), which 

 is ultimately carried up with them (fig. 775 c), leaving often a sheath 

 (vaginula) round the bottom of the fruit-stalk. These pistillidia 

 finally become the thecae (fig. 774) or spore-cases, supported on a 



7", 



stalk or seta which has leaves at its base, called perichastial 

 around, and #/V>j f a bristle) leaves; on removal of the calyptra, the 

 theca is found to consist of a case with an operculum or lid (fig. 



Figs. 774-777. Figures to illustrate' the natural order Musci. 



Fig. 774. Funaria hygrometrica slightly magnified /, Leaves, those connected with the 

 seta being called perichaetial. ti, Urn-like theca, sporangium or spore-case supported on a long 

 twisted stalk or seta, p. c, Calyptra, which exists on one of the thecae, and has fallen from the 

 other, o, Operculum or lid. 



Fig. 775. Theca of Encalypta vulgaris. u, Theca or spore-case, c, Mitriform entire calyptra. 

 o, Operculum or lid. s, Top of the seta. The calyptra is transparent, and the operculum and 

 theca are seen through it. 



Fig. 776. The same theca, , with the calyptra removed, o, Operculum detached, showing 

 the peristome, p, with its sixteen cilia or teeth. 



Fig. 777. Very young theca of Splachnum cut longitudinally, a, Apophysis or swelling of 

 the seta at the base of the theca. c, Central columella. s, Cavity or bag between the columella 

 and the walls of the theca, containing spores. The integument of the theca is formed of different 

 cellular layers; the first, e, forms the epidermis, and is thickened at the summit to form the 

 operculum; there are then two intermediate layers, which ultimately form the teeth of the 

 peristome; and lastly, an inner integument, s, which forms the parietes of the spore-bearing 

 cavity. 



