VII. ISOETES. 915 



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

 composition of philters. 



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

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

 hot-houses, as a covering for damp walls or borders : such are & apoda, denticulata, Huyelii, ccesia, and 

 cuspidnta as a sarmentose plant. Two or three species possess the property of drying up and revivin" 

 when moistened (& cvnvaluta, involoens, &c.) ; thus recalling the Rose of Jericho (see p. 232). 



VII. ISOETES, Bartling. 



Aquatic and submerged Acotyledons, or terrestrial. RHIZOME very short, furrowed, 

 emitting dichotomous roots and subulate ccespitose fronds, erect in evolution, enlarged 

 and membranous at the base. SPORANGIA situated at the lower part of the fronds, those 

 containing macrospores attached to the outer fronds ; those containing microspores 

 attached to the central fronds of the rosette ; the macrospores are marked on one hemi- 

 sphere with a tricrural line, the microspores are marked with a furrow. 



Perennial grass-like PLANTS, aquatic or amphibious 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 which it divides, by a sort of budding 

 process, into distinct individuals (Isoetes 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. FRONDS 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 found. 



Following J. Gay, A. Braun distinguishes in the frond the phyllopode, the 

 pouch (le voile), the border (I'area), 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 

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

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

 peculiar tissue (I'area) circumscribes it. The pouch encloses a membranous sac 

 (sporangium), closed on all sides, which is divided transversely into several compart- 

 ments by membranous septa. Above the sporangium is a small smooth scale, formed 

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

 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 central 

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

 stomata, which are absent in the lacustrine. 



The SPORANGIA, although alike in form, structure, and insertion, contain 2 



3N 2 



