Fig. 1091. Isoetes lacrtstris. Lake Quill-wort. The stem is email and conn- 

 like, aud bears its leaves, whicb are linear-cylindrical, in tufts. 



Lycopodium. — L.davatum, the Common Clnb-moss, possesses well-marked 

 emetic and purgative properties, and is also reputed diuretic aud emmena- 

 gogue. The spoi-es 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 kno-^\Ti as vegetable sulphur. Besides their 

 tise in medicine, as just alluded to, they are sometimes employed in phar- 

 macy for covering pills, the object sought being, to render them tasteless 

 and prevent their adhering together. Lycopodium spores, however, from 

 tbeu- inflammable nature, are principally used in the preparation of fire- 

 works, and for the i)roduction of anificial lightning at the theatres, &c. 

 L. Selago has similar medicinal properties, but it sometimes acts as a nar- 

 cotico-acrid poison. The spores are of a like inflammable nature to those of 

 L. davatum. L. catharticum is said to be a powerful purgative. 



Natural Order 290. Mrsci.— The Moss Order {fig. 1092).— 

 Character. — Cellular plants {figs. 8, 9, and 805), terrestrial 

 or aquatic, with erect or creeping stems, and usually spirally 

 imbricated leaves {fig. 1092). Eijyroductive organs of two kinds, 

 called antheridia and archegonia (see pages 366 — 370), which 

 are either placed on the same or on separate plants {figs. 8 and 9). 

 The antJieridiurii {fig. 802) is a more or less rounded, elliptic, 

 or cylindrical sac, containing, when mature, a number of minute 

 cells {zootheccB), each of which encloses a spirally twisted fila- 

 ment {anihcrozoid ov jphytozoon). The archeganium is usually a 



