470 



THE DICTIONARY OF GARDENING, 





Spharopsidese continued. 



with brown, oblong or lanceolate sporidia, made up of 

 a row of three or more cells; Phoma and Phyllosticta, 



ff& 



FIG. 511. PHOMA HERBARUM-, Pycnidia in transverse section, 

 x 20, one opened; b, Conidia still on the Stalks, x 400; 

 e, Conidia free, after falling off the Stalks, x 400. 



with transparent, elliptical, one-celled sporidia (see Fig. 

 511); Septoria, with long, slender, thread-like, pale 

 eporidia; Sphaeropsis, with elliptical, brown, one-celled 

 sporidia; Stagonospora, like Hendersonia, but sporidia 

 pale. The pycnidia are very similar in all the genera; 

 but Ascochyta, Phyllosticta, and Septoria usually cause a 

 discoloured spot on the leaves or stems of plants, in 

 which the pycnidia are grouped. Such spots are seldom 

 caused by the species of the other genera. 



SPH2EROPTERIS (from sphaira, a globe, and 



pteris, a Fern ; alluding to the globose involucres). OBD. 



Filices. A monotypic genus, the species being a stove 



Fern. For culture, see Ferns. 



S. barbata (bearded), fronds 2ft. to 3ft. long, tripinnate ; pin- 

 nules oblong, deeply pinnatitid. sori globose, on the back of a 

 vein or veinlet ; receptacle large ; involucre inferior, globose, 

 stipitate, at first inclosing the whole sorus, at length bursting 

 vertically into two spreading lobes or lips. Nepaul, Sikkim, &c. 

 cyath 



Included under ScMzandra 

 Included under Didy- 



SYN. Peranema cyatheoides. 



SPH2EROSTEMA. 

 (which see). 



SPHJEROSTEFHANOS. 

 mochlcena. 



SPH2EROSTIGMA. Included under CEnotliera 

 (which see). 



SPH2BROTELE (of Link). Included under Urceo- 

 lina (which see). 



SPHJEROTHELE. Included under Stenomesson 

 (which see). 



SPHAGNUM (from Sphagnos, Moss). A genus of 

 Mosses, found in all countries of the colder temperate 

 zones. There are numerous species, but all delight in 

 swamps, or in water; and they have, therefore, received 

 the name of Bog-mosses. Seventeen species, and many 

 varieties, have been recognised as British. So different 

 is the genus Sphagnum from other Mosses in many 

 respects, that it is placed in a distinct family, called 

 Sphagnaceoe. It is easily recognised by the swampy 

 habitats; by its erect stems, several inches long, and 

 destitute of root-hairs ; branches in clusters of from 

 two to six, at frequent intervals along the stems, some 

 spreading, others reflexed; male organs on lateral 

 branches resembling small catkins; female organs in 

 lateral branches like buds; capsules at first apparently 

 sessile, then supported on short stalks, and conspicuous, 

 globose, and bursting (often explosively) by a false lid, 

 unlike the lids in true Mosses. The microscope shows 

 peculiar structures also in the stems and leaves of 

 Sphagnum, which deserve notice here, as they bear on 

 the uses of the Mosses in gardening work. The middle 

 of each stem consists of a mass of small cells, of a 

 brown colour, inclosed in a layer of smaller and darker 

 brown cells, with thicker walls. This structure is much 

 like that of the stem of any common Moss. But the 

 stems of the species of Sphagnum have an outer covering, 

 composed of from one to four layers (according to the 

 species) of much larger, transparent cells, with thin 

 walls, which in most are pierced with holes, leading 

 from cell to cell. The leaves are numerous, and are 

 sessile, small, aud more or less pointed. They have no 



Sphagnum continued. 



midribs, and consist of a single layer of cells, among which 

 there are two very different forms the one long and 

 narrow (inclosing protoplasm and chlorophyl bodies), form- 

 ing a network, with large meshes, each filled by a trans- 

 parent cell ; the second form usually showing a thickening 

 deposit in the shape of fibres, coiled in the interior round 

 the walls, which are pierced by holes like those in the 

 cells of the layers surrounding the stem. As in the 

 latter, the transparent cells in the leaves, when mature, 

 contain no protoplasm or chlorophyl. Their special 

 duty is to suck in water from the swampy soil through 

 the holes in their walls, and to pass it on from cell 

 to cell upwards. They thus do the work of root-hairs, 

 which are not present in these plants. This structure 

 renders the Mosses of the genus Sphagnum almost as 

 absorbent as a sponge, as may be easily proved by 

 squeezing the water out of a clump of Moss, and again 

 dipping the latter into water. The species all grow in 

 compact tufts or mosses, often covering a considerable 

 area. The plants tend to grow upwards, and to die in 

 proportionate rate below. Some of the branches grow 

 so large as to give the appearance of bifurcations of 

 the stems; and, as these die away below, the stems and 

 branches become separated, and form new plants. In 

 this way, one form of multiplication of the individuals 

 is secured. Reproduction is also effected by the spores, 

 produced in the capsules. These are quadrangular in 

 form. If they fall on damp soil, they produce flattened, 

 branched, thin, green plates, on which Moss-plants grow 

 from small buds. If the spores fall into water, they pro- 

 duce slender, branched, green threads, like those of other 

 Mosses ; and on these buds are formed, from which the 

 Moss-plants grow. 



The Bog-mosses are very important agents in the 

 production of Peat Mosses and swamps, as they prevent 

 the water from flowing away, and, by growing upwards 

 and dying away beneath, add to the depth of the peat, 

 though peat formed by them requires a long time to 

 become firm suitable for fuel. 



Uses. In gardens, Sphagnum is of much use, inas- 

 much as, when dry, it makes admirable packing material, 

 being light, firm, and very elastic. The power of 

 absorbing and retaining moisture renders the wet 

 Sphagna excellent for packing round cuttings and young 

 plants to be sent to a distance, as they supply water 

 when it is needed. These Mosses are also much used 

 in greenhouses for growing epiphytal Orchids or 

 other plants of similar habits, which require plenty of 

 moisture. 



SFHENANDRA (from sphen, a wedge, and aner, 

 andros, a male or anther ; alluding to the shape of the 

 anthers). OBD. Scrophularinece. A monotypic genus. 

 The species is a greenhouse, viscous-pubescent, annual 

 or perennial herb. It thrives in loamy soil, and may 

 be increased by seeds. 



S. viscosa (clammy), fl. violet, pedicellate, loosely racemose ; 

 calyx five-parted ; corolla broadly rotate, with five broad, entire, 

 spreading lobes ; stamens four. June. I. mostly opposite, 

 oblong-lanceolate, with a few teeth ; floral ones much smaller, 

 ovate, entire, very acute or bract-like. A. 1ft South Africa, 

 1773. (B. M. 217, under name of Buchnera viscosa.) 



SPHENODESMA (from sphen, a wedge, and desme, 

 a fascicle; alluding to the form of the inflorescence). 

 SYNS. Roscoea (of Roxburgh), Viticastrum. OBD. Ver- 

 benaceae. A genus consisting of about eight species of 

 stove, climbing shrubs, natives of the Eastern provinces 

 of India and the Malayan Archipelago. Flowers in rather 

 small, pedunculate, sessile cymes ; calyx five-toothed ; 

 corolla tube short, the limb spreading, of five ovate or 

 oblong lobes ; stamens five. Leaves 'opposite, entire. 

 S. pentandra, the only species introduced, thrives in sandy 

 loam. It may be increased by cuttings, inserted in sand, 

 under a glass in heat. 



