704 HEPATICACEA. 
of lid (operculum) (figs. 826, 0, and 827). The sporangium 
usually opens when ripe in a transverse manner from the sepa- 
ration of the operculum (figs. 826, 0, and 827), or sometimes by 
splitting vertically into four equal valves, which are connected 
at the summit by the persistent operculum (jig. 1121, a); or 
rarely it dehisces irregularly. At the dehiscence of the spor- 
angium, its mouth (stoma) is seen to be either surrounded by a 
peristome, consisting of one (aploperistomous) or two rows 
(diploperistomous) of teeth (fig. 826, p) ; or the mouth is naked 
(gymnostomous). 
Division of the Order and Illustrative Genera.—This order is 
commonly divided into four sub-orders, which are frequently 
regarded as separate orders, the principal distinctive characters 
of which are as follow :— 
Sub-order 1. Sphagnacee or Sphagnee.—Bog-mosses. Sporan- 
gium globular, surrounded at the base by the calyptra; the 
columella does not reach to the apex of the capsule. The 
only genus is Sphagnum, Dill., which is found on boggy 
moors and in damp woods. 
Sub-order 2. Andreacex or Andreex.—Split-mosses.— Sporan- 
gium splitting vertically into four valves, but remaining con- 
nected at the summit. Illustrative Genus :—Andrea, Ehr. 
(fig. 1121). 
Sub-order 3. Phascacex or Phascex.—The sporangium does not 
burst ; the spores escaping by the decay of the wall of the 
sporangium. Illustrative Genus :—Phascum, Linn. 
Sub order 4. Bryacex or Bryex. — Urn-mosses. —Sporangium, 
which is generally borne upon a seta of considerable length, 
dehiscing transversely by the separation of the operculum 
(figs. 826 and 827). Illustrative Genera :—Funaria, Hedgw. ; 
Polytrichum, Linn. 
Distribution and Nuwmbers.—They are generally diffused over 
the globe, but most abundantly in temperate climates. There 
are about 1,250 species. 
Properties and Uses. —Of little importance either in a medi- 
cinal or economic point of view. Some species are reputed to 
possess astringent and diuretic properties, but none are employed 
by the medical practitioner in this country. The species of 
Sphagium furnish food to the reindeer, and even to man in the 
polar regions. 
Order 2. Hepaticace&, the Liverwort Order (see pages 
375-377).—Character. —Smull cellular plants, either with 
a creeping stem bearing minute imbricate leaves (fig. 1122) or 
with a lobed thalloid expansion (jigs. 830 and 832). Repro- 
ductive organs of two kinds, called antheridia and archegonia, 
which are either on the same plant or on different ones ; hence 
these plants are monecious or diccious. The antheridia are 
