AN ENCYCLOPEDIA OF HORTICULTURE. 



435 



SilpMnm continued. 



opposite, or whorled, entire, toothed, or lobed. The best- 

 known species are described below. Dr. Asa Gray gays 

 of 8. laciniatum : " On the wide, open prairies the leaves 

 are said to present their faces uniformly north and south, 

 whence it is called the Compass-plant " ; this peculiarity, 

 according to other authorities, is more noticeable in 

 young specimens. Any ordinary soil is suitable for the 

 culture of these plants, which are best placed at the 

 backs of flower-beds. They may be increased by division. 



Fio. 486. INFLORESCENCE ATO LEAP OP SILPHIUJI LACTSIATUM. 



S. laciniatum (torn).* Compass Plant ; Pilot Weed ; Polar 

 Plant. JL-headt few, lin. to 2in. broad, somewhat racemose; 

 involucral scales rigidly pointed ; acbenes broadly winged. July. 

 L pinnatipartite, petioled but dilating and clasping at base, the 

 lower and radical ones ovate, 1ft to 24ft long ; divisions lanceo- 

 late or linear, acute, cut-lobed or pinnatifid, rarely entire. A. 3ft 

 to 6ft. Plant rough-bristly. See Fig. 485. (B. M. 6554.) 



S. perfoliatum (perfoliate-leaved). JL-heads corymbose ; achenes 

 winged and variously notched. July. I. entire, ovate, 6in. to 

 15in. long, coarsely toothed, the upper ones united by their bases, 

 and forming a cup-shaped disk, the lower ones abruptly nar- 

 rowed into winged petioles, which are connate by their bases. 

 Stem 4in. to Sin. high, square. (B. M, 3354.) 



S. terebinthinacenm (terebinthine). Prairie Dock. Jt.-headt 

 small ; involucral scales roundish, obtuse, smooth ; achenes nar- 

 rowly-winged. July to September, t ovate and ovate-oblong, 



Silphium continued. 



somewhat cordate, serrate-toothed, rough, especially beneath, 

 1ft. to 2ft long, on slender petioles. Stem smooth, 4ft to 10ft 

 high, panicled at the summit, and bearing many heads. (B. M. 



S. trlfollatum (three-leaved). JL-headt loosely paniculate; 

 achenes rather broadly winged. August /., cauline ones lanceo- 

 late, pointed, entire or scarcely serrate, rough, short-petioled, 

 in whorls of three or four, the uppermost ones opposite. Stem 

 smooth, rather slender, 4ft to 6ft high, branched above. 

 (B. M. 3355.) 



SILVER BELL TREE. See 



SILVER BERRY. The fruit of Elceagnus argentea. 



SILVER BRACTS. A common name for Cotyledon 

 Pachyphytum. 



SILVER BUSH. A common name for Anthyllis 

 Barba-Jovis. 



SILVER CEDAR. See Juniperos virginiana 

 glanca. 



SILVER FIR. The popular name for Abie* pectinata. 



SILVER-GRAIN. The glittering plates, in ex- 

 ogenous wood, caused by the division of the medullary rays. 



SILVER ROD. A common name for Asphodelu* 

 ramosus. 



SILVER -TREE. See Leucadendron argen- 

 terun. The name is also applied to Elaragnus. 



SILVER WEED. See Argyreia. The name is 

 also used for Potentdla Anterina. 



SILVER Y MOTH. See Plusia. 



SILYBUM (an old Greek name, applied by Dios- 

 corides to some Thistle-like plants). OBD. Comj ofitae. A 

 monotypic genus. The species is a glabrous, erect, bi- 

 ennial herb, included, in some book?, under Carduus. 

 " The specific name, Jfan'anum, was given to this plant 

 to preserve the legend that the white stain on the leaves 

 was caused by the falling of a drop of the Virgin Mary's 

 milk" (Lindley). The plant was formerly cultivated for 

 culinary purposes, the root being boiled as a potherb, 

 the heads treated like those of Artichokes, and the 

 leaves used as a spring salad. It occurs in waste places, 

 near gardens, &c., but is not indigenous to Britain. Any 

 ordinary soil is suitable for its culture. Propagated by 

 see'ds. 

 S. Mariamun (St Mary's).* Blessed, Holy, or Our Lady's Milk 



Thistle. Jl.-head* rose-purple, globose, lin. to 2in. in diameter ; 



involucral bracts coriaceous, closely appressed, with one very 



stout, terminal spine ; receptacle fleshy, hairy, not pitted. July 



to September. large, alternate, sinuately lobed or pinnatifid, 



white-spotted above ; teeth or lobes spiny, h. 1ft to 4ft South 



Europe, Ac. (Sy. En. B. 681.) 



(the native name in Guiana of one of the 

 species). STN. Zwingera. OBD. Simarubece. A genus 

 comprising about fourteen species of stove, evergreen or 

 deciduous trees or shrubs, natives of South America. 

 Flowers small or rather large ; calyx small, four or five- 

 lobed ; petals four or five, longer than the calyx, spread- 

 ing, valvate ; disk narrow, erect ; stamens eight to ten, 

 included ; panicles loose-flowered, short or elongated. 

 Carpels one to fire, drupaceous, the endocarp usually 

 hard. Leaves alternate, impari- or abruptly pinnate, 

 rarely one to three-foliolate ; leaflets entire, coriaceous. 

 Three species have been introduced, but S. Cedron is 

 probably the only one now known in cultivation in this 

 country. This is a small tree, remarkable for the febri- 

 fugal properties of its seeds, which have also been, from 

 time immemorial, reputed, in its native place, as a 

 remedy for snake-bites. It thrives in well- drained, turfy 

 loam. Propagated by cuttings of the ripened wood, in- 

 serted in sand, under a glass, in heat; or by imported 

 seeds. 



S. Cedron. Cedron-tree. ft. disposed in racemes 3ft to 4ft 

 long. May. /r. about the size of a swan's eg-:, one-seeded, four 

 of the cells being barren. I. large, pinnate ; leaflets twenty or 

 more, narrow-elliptic, livid-green above, paler beneath. Trunk 

 simple, erect slender, h. 20ft Xew Granada, 1846. 



