CRYPTOGAMOUS OR FLOWERLESS PLANTS. 497 



dom more than one in a flower maturing) becomes the capsule, 

 which is rarely indehiscent or splitting by four longitudinal slits, 

 but usually opens by a lid (operculum) : beneath the lid and aris- 

 ing from the mouth of the capsule are commonly either one or 

 two rows of rigid processes (collectively the peristome), which are 

 always some multiple of four : those of the outer row are called 

 teeth, of the inner, cilia. An elastic ring of cells (annulus) lies 

 between the rim of the capsule and operculum. The powdery 

 particles filling the capsule are spores. The thread-like stalk (ped- 

 icel) supporting the capsule is inserted into the elongated torus 

 (vaginuld) of the flower. The pedicel continued through the cap- 

 sule forms the columella : enlarged under the capsule it sometimes 

 forms an apopliysis. The calyptra separating early at its base is 

 carried up on the apex of the capsule ; if it splits on one side it is 

 hood-shaped or cuculliform, if not, it is mitre-shaped or mitriform. 

 Intermixed with the reproductive organs are jointed filaments (par- 

 aphyses). The leaves next the antheridia are called perigonial 

 leaves, those around the pistillidia or pedicel the perichcetial leaves. 



938. Ord, HepaticSB (Liverworts). Frondose or Moss-like plants, 

 of a loose cellular texture, usually procumbent and emitting root- 

 lets from beneath ; the calyptra not separating from the base, but 

 usually rupturing at the apex ; the capsule not opening by a lid, 

 containing spores usually mixed with elaters (which are thin, 

 thread-like cells, containing one or two spiral fibres, uncoiling elas- 

 tically at maturity). Vegetation sometimes frondose, i. e. the 

 stem and leaves confluent into an expanded leaf-like mass ; some- 

 times foliaceous, when the leaves are distinct from the stern, as in 

 true Mosses, entire or cleft, two-ranked, and often with an imper- 

 fect or rudimentary row (amphigastria) on the under side of the 

 stem. Reproductive organs of two kinds, viz. antheridia and 

 pistillidia, much as in Mosses (937), variously situated. The 

 matured pistillidium forms the capsule, which is either sessile or 

 borne on a long cellular pedicel, and dehiscent by irregular open- 

 ings, by teeth at its apex, or lengthwise by two or four valves. A 

 columella is rarely present. The perianth is a tubular organ in- 

 closing the calyptra, which directly includes the pistillidium. Sur- 

 rounding the perianth are involucral leaves of particular forms. 

 The antheridia in the foliaceous species are situated in the axils of 

 perigonial leaves. 



939. Subord, Ricdacea; are chiefly floating plants, rooting from 

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