NATURAL ORDERS. 295 



tend upward : Uie plant therefore grows from its summit, hence the name aero- 

 gens (Irora akros, summit). The leaves are terminal, and when young are rolled 

 up in a circinate manner peculiar to ferns ; the fruit is borne on the margin of con- 

 tracted leaves, as the spore-cases upon the leaves of Osmunda and othor ferns. 



563. LycopoDiACEiE, the Club-Moss Tribe. — Moss-Uhe plants, 

 with creeping or erect leafy stems. Lea/ves narrow, simple, en- 

 tire. Thecce sessile in the axils of the leaves, 1-3-cellecl, open- 

 ing by valves or indehiscent, containing minute grains like line 

 powder, or a few sporules ; sometimes both kinds are found on 

 the same j)lant. 



a. Properties: some Lijcopodmms are emetic and cathartic. The powdery mat- 

 ter in the thecoe is inflammable, and employed under *tlie name of lycopode, or 

 vegetable brimstone. 



Genus. — Lycopodium. 



564. Marsileacejs, the Pepperwort Tribe. — Creeping o\ float- 

 ing plants. Leaves usually stalked, sometimes sessile and scaly. 

 Reproductive organs inclosed in involucres, and of two kinds : 

 the one stalked, or sessile clustered, membraneous sacs, contain- 

 ing nitinute graniiles, sometimes considered as pollen ; the other 

 membraneous sacs containing simple oval cells, only one of 

 which is developed as a germinating body. 



Genus. — Salvima. 



Class IY. — Anophytes. 



665. Musci, Mosses. — Erect or creeping, terrestrial or aquatic 

 plants, found in the most northern latitudes which are known 

 to produce vegetation : they have a distinct axis of growth, and 

 are covered with minute, imbricated, entire, or serrated leaves. 

 Reproductive organs of two kinds : Antheridia^ consisting of 

 minute cylindrical sacs, containing a multitude of spherical or 

 oval particles. Pistillidia^ flask-like bodies, 

 each furnished with a membraneous covering Fig. 217. 



{calyptrd) mixed with empty, jointed ^d,- 

 vci^ViX&OY pajrap)hyses. The pistillidium when 

 rijDe becomes the capside^ usually opening by 

 a lid [pperculuni).^ showing the mouth of the 

 capsule naked, or crowned by one or two 

 rows of cellular rigid processes called peris- 

 tome. 



Genera. — Funaria, Polytrichum. 



Fig. 217, young spore-cases and paraphyses of Mirium 

 cuB^pldatuin. 



^"566. Hepatic^, Liverioorts. — Cellular plants growing in 

 earth, or trees in damp places ; consisting of an axis or stem 

 which is leafless, or the stem and leaves are confluent into an 

 expanded leaf-like moss. Reproductive organs of two kinds : 



