ISATUEAL ORDERS. 
295 
tend upward : the plant therefore grows from its summit, hence the name acro- 
gens (from 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 other ferns. 
563. Lycopodiace^, the Club-Moss Tribe, — Moss-like plants, 
with creeping or erect leafy stems. Lemes narrow, simple, en- 
tire. TheccB sessile in the axils of the leaves, 1-3-celled, open- 
ing by valves or indehiscent, containing minute grains like fine 
powder, or a few sporules ; sometimes both kinds are found on 
the same plant. 
a. Properties : some Lycopodmms are emetic and cathartic. The powdery mat- 
ter in the thecae is inflammable, and employed under the name of lycopode, or 
vegetable brimstone. 
Genus. — Lycopodium. 
564. Maksileace^, the Pepperwort Tribe. — Creeping or float- 
ing plants. Lemes usually stalked, sometimes sessile and scaly. 
Reproduetiwe organs inclosed in involucres, and of two kinds : 
the one stalked, or sessile clustered, membraneous sacs, contain- 
ing minute granules, 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. 
565. 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 w^ith 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 2^^- 
{calyptra) mixed with empty, jointed fila- 
ments or parojphyses. The pistillidium when 
ripe becomes the capsule., usually opening by 
a lid {operculum)., 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 
euspidatum. 
566. Hepaticje, Liverworts. — Cellula/r 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-likf moss. Reproductive orsfans of two kinds : 
