SCARIDIUM. 



[ 565 ] 



SCHISTOSTEGE^E. 



or less circular plates of cellular tissue, the 

 cells presenting a radiated arrangement from 

 the centre, by which they are ordinarily 

 attached; the margins are usually toothed 

 or fringed more or less regularly by the 

 prolongation of the free ends of the cells. 

 They are closely related to stellate hairs, 

 such as those of ivy, of Deutzia (PI. 21. 

 figs. 26,27), &c., and may be regarded as more 

 highly developed forms of these. They are 

 particularly remarkable on the epidermis of 

 certain plants, which exhibit a kind of scurfy 



Fig. 631. 



Scale of the epidermis of Hippophae rhamnoides. 

 Magnified 50 diameters. 



surface, for example the Eleagnaceae (fig. 

 631), the Bromeliaceae, some Rhododendra, 

 and the lower surface of the leaves of many 

 ferns; they must be distinguished in the 

 last case from the ramenta of the stems, 

 which are attached by the base, and not by 

 a central pedicle. 



BIBL. See HAIRS and EPIDERMIS. 



SCARIDIUM, Ehr. A genus of Rota- 

 toria, of the family Hydatina3a. 



Char. Eye single, cervical; rotatory organ 

 armed with a hooked bristle in front ; foot 

 forked, very long, adapted for leaping. 



Lateral processes of jaws bifurcate, so as 

 to present two teeth each. 



S. longicaudum (PI. 35. fig. 27). Foot as 

 long as or longer than the body, toes shorter 

 than the foot. Aquatic ; length 1-72". 



BIBL. Ehrenberg, Infus. p. 439. 



SCENEDESMUS, Meyen. A genus of 

 Desmidiaceae. 



Char. Cells fusiform or oblong, arranged 

 side by side in a single row of from two to 

 ten, after division forming two alternating 

 rows ; division oblique ; terminal cells often 

 lunate, or with a bristle at each end. 



Six species (Ralfs). 



S. quadricauda (PI. 10. fig. 50). Cells 

 generally four, oblong, rounded at the ends, 

 in a single row, terminal cells with a bristle 

 at each end. Common; length of cells 

 1-1120". 



S. obliquus (PL 10. fig. 51). Cells ellip- 

 tico-fusiform, after division arranged in two 



distinct and generally oblique rows, end cells 

 lunate. Length 1-1670". 



S. obtusus (PI. 10. figs. 53 & 54, just after 

 division). Cells three to eight, ovate or 

 oblong, all alike, arranged in one row, or 

 after division alternately in two rows. Com- 

 mon; length 1-2330 to 1-1960". 



BIBL. Ralfs, Brit. Desmid. p. 189. 



SCEPTRONEIS,Ehr. An obscure genus 

 of fossil Diatomaceae. 



BIBL. Ehrenberg, Ber. d. BerL Akad. 

 1844. p. 264. 



SCHISMA. A genus of Jungermannieaj 

 (Hepaticaceae), founded on a rare British 

 form, S. (Jung.)juniperina, /3 europaa, found 

 among rocks on the mountains of Scotland, 

 Ireland and Wales. It grows 3 to 6" high, 

 and is rarely found in fruit. 



BIBL. Hook. Brit. Flor. ii. pt. 1. p. 124, 

 Brit. Jung. pi. 4 ; Ekart, Syn. Jung. pi. 8. 

 fig. 62; Endlicher, Gen. Plant. Supp. 1. No. 

 472-17. 



SCHISTOSTEGE^. A family of oper- 

 culate Acrocarpous (terminal-fruited) Mosses, 

 of gregarious habit. Stem naked below, 

 foliaceous in two manners above; sometimes 

 frond-like or fern-like, composed of leaves 

 attached vertically and connected at the base, 

 with dense areolations, consisting of rhom- 

 boidal prosenchymatous, pellucid or green 

 cells; sometimes with small leaves, like 

 those of other Mosses, horizontal and 

 arranged quincuncially. All the leaves 

 nerveless and flat. Capsule without an 

 annulus, very minute, globular-oval, with a 

 very small convex operculum (figs. 632-635). 



British Genus. 



SCHISTOSTEGA. Calyptra cylindrically 

 bell-shaped. Inflorescence dioecious, plants 

 similar. 



The only species of this genus, the elegant 



Fig. 632. 



Schistostega osmundacea. 

 saves of barren branches. 



little Sch. osmundacea, Web. and Mohr, 



Fig. 632. Leaves of barren branches. Magnified 50 

 diameters. 



