708 SYSTEMATIC BOTAXY. 



{fig. 156): consisting of either one kind of sporangium called 

 the pollen-sporangium; or commonly of two, called oosporangia 

 {fig. 798), and pollen-sporangia {figs. 796 and 797). The pollen- 

 sporangia {fig. 797) contain a number of small spores {micro- 

 spores); and the oosporangia enclose 4 large spores {viacrospores) 

 {fig. 798). (See pages 374, 375.) 



Distribution, ^c. — They are almost universally diffused, oc- 

 curring in cold, temperate, and warm climates. Examples: — 

 Lycopodium, Selaginella, Isoetes. There are 6 genera, and 

 about 200 species. 



Properties and Uses. — Many species contain an acrid prin- 

 ciple. In moderate doses they are frequently emetic and pur- 

 gative, but in large doses they sometimes produce poisonous 

 effects. Some are reputed to possess aphrodisiac properties. 

 The spores are inflammable. 



Lycopodium — L. clnvatum, the Common Club-moss, possesses well-marked 

 emetic and purgative properties, and is reputed diuretic and emmenagogue. 

 The spores have been employed externally, for their absorbent qualities, in 

 erysipelas, and various cutaneous affections ; and internally, they are said to 

 be diuretic, sedative, and demulcent. These spores are of a yellow colour, and 

 are sometimes known as vepelahle sulphur. Besides their use in medicine as 

 alluded to above, they are employed in pharmacy for covering pills, the object 

 sought being, to render them tasteless and prevent their adhering together. 

 Lycopodium spores, however, from their inflammable nature, are principally 

 used in the preparation of tire-works, and for the production of artificial light- 

 ning at the theatres, &c. L. Selngo has similar medicinal properties, but it 

 sometimes acts as a narcotico-acrid poison. The i^pores are of a like nature 

 to those just noticed. L. catharticum is said to be a powerful purgative. 



Natural Order 290. Musci. — The Moss Order. — Cellular 

 plants (^ys. 154, 155, and 802), terrestrial or aquatic, with erect 

 or creeping stems, and usually spirally imbricated leaves. Re- 

 productive organs of two kinds, called antheridia and archegonia. 

 (See pages 375 — 378), which are either placed on the same, or 

 on separate plants {figs. 154 and 155). The antheridium (fig. 

 799) is a more or less rounded, elliptic, or cylindrical sac, con- 

 taining when mature, a number of cells {zootheccc), each of which 

 encloses a spirally twisted filament {phy(ozoon). The arche- 

 gonium is usually a flask-shaped body (fig. 800), which after 

 fertilization developes an urn-shaped sporangium (figs. 803 and 

 804) with a central columella {fig. 807) ; the space between 

 which and the walls of the sporangium being occupied by 

 spores, without any elatcrs among them. The sporangium 

 is commonly placed on a stalk {seta) {figs. 801, t, and 802,/)), 

 and at first is covered by a hood {cahjptra) {figs. 802 and 

 803 c), beneath which is a kind of lid {operculum) {figs. 804, o, 

 and 805). The sporangium usually opens when ripe in 

 a transverse manner from the separation of the operculum 

 {fig. 805) ; or sometimes by splitting vertically into four 

 equal valves, which arc connected at tlie summit by the persist- 

 ent operculum {fig. 1091, a); or rarely irregularly. At the dc- 



