VII. ISOETE^. 915 



vellous virtues in checking vomiting, curing pulmonary afFections, dropsy, &c. ; they also use it in the 

 composition of philters. 



Some species of Lycopodiaceee are cultivated ; the true Lycopods are very difficult to rear, but this 

 is not the case with SelagineU(e, several of which play a considerable part in the ornamentation of our 

 hot-houses, as a covering for damp walls or borders : such' are 8. apoda, denticulata, ffttgelii, ceesia, and 

 cusptduta as a sarmentose plant. Two or three species possess the property of drying up and reviving 

 when moistened (S. oon^'ohttft, iiivaloens, &c.) ; thus recalling the Rose of Jericho (see p. 232).. 



VII. ISOETE^, Bartling. 



Aqitatic and submerged Acotyledons, or terrestrial. Rhizome very short, furrowed, 

 emitting dichotomous roots 'and subulate coespitose fronds, erect in evolution, enlarged 

 and memhranous at the tctse. Sporangia situated at the lower part of the fronds, those 

 containing m,acrospores attached to the outer fronds; those containing m,icrospores 

 attached to the central fronds of the rosette ; the m,acrospores are marhed on one hemi- 

 sphere with a tricrural line, the microspores are m-arleed with a furrow. 



Perennial grass-like plants, aquatic or ampMbious or terrestrial, stemless. 

 Rhizome sub-globose or depressed, formed of a fleshy utricular tissue, often oily, 

 bearing below 2-3-4 furrows or fissures, along wbich it divides, by a sort of budding 

 process, into distinct individuals {Isoetea setacea, &c.). Roots often springing in 

 longitudinal series in each of the furrows of the stock, dichotomous, brown, almost 

 glabrous in the lacustrine species, velvety in the terrestrial." Feonds fascicled, 

 straight in vernation, their base more or less amplexicaul, and pressed together like 

 a bulb, terminated by a foliar linear-filiform or subulate blade, resembling the leaves 

 of some Phsenogams {Littorella, Lobelia Dortmanna, &c.), along with which Isoetes 

 is often foiind. 



FpUpwing J. Gay, A, Br^un distinguishes in the frond the phyllopode, the 

 pouch {le voile), the border [I'ar.ea], the sporangium, the ligule, and the blade. The 

 phyllopode is the dilated or sheathing base of the frond, an organ analogous to the 

 petiole of a leaf. In the terrestrial species the phyllopodes persist for several years, 

 on the outside of the rhizome, as brown, hard, 2-3-toothed scales. The phyllopode is 

 hoUowpd into a pouch (le voile), which occupies almost its whole surface ; this pouch 

 either opens towards the axis, or is perforated at the bage, A narrow border of a 

 peculiar tissue {I'ared) circumscribes it. The pouch encjoses a membranous sac 

 (sporangium), closed on all sjdes, which is divided transyersely into several compart- 

 ments by membranous septa. Abof e the sporangium is a small smooth scale, foj-med 

 of a delicate tissue (ligule). The rest of the frond, qf a more or less deep green, fprms 

 the blade ; it is usually subulate, flat on the inner surface, convex on the outer ; 

 it is traversed longitudinally by transversely septate tubes, which surround a pentral 

 bundle of annular and spiral vessels. The epidermis of the terrestrial species bears 

 stomata, which are absent in the lacustrine. 



The SPOKANGiA, although alike in form, structure, and insertion, contain. 2 



3n 2 



