Sempervivum

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Plant Characteristics
Origin: ?
Cultivation
Exposure: ?"?" is not in the list (sun, part-sun, shade, unknown) of allowed values for the "Exposure" property.
Water: ?"?" is not in the list (wet, moist, moderate, dry, less when dormant) of allowed values for the "Water" property.
Scientific Names



Read about Sempervivum in the Standard Cyclopedia of Horticulture 

Sempervivum (Latin, living forever). Crassulaceae. Houseleek. Thick fleshy usually stemless, perennial herbs or subshrubs which are used for carpet-bedding, rockeries, and the like. See Succulents (p. 2672, Vol. V) for culture.

Leaves alternate, thick-fleshy, often revolute: cymes panicled, usually densely: fls. white, rose, green, yellow, or purple; calyx 6- to many-cleft or -parted, rarely 5- cleft; petals 6 to many, free or connate at the base, oblong or lanceolate; stamens double as many as the petals, rarely the same number, free; ovary with as many carpels as petals, free or the base or up to the middle immersed in the calyx-tube: fr. many-seeded follicles.—About 65 species, widely scattered in the mountains of the Old World. The genus was monographed (horticulturally) by J. G. Baker in Gardener's Chronicle for 1879, and his treatment has been followed here to some extent with the addition of several species and slight modifications to meet more recent knowledge of the genus. Sempervivum is closely related to Sedum, but the floral parts are multiples of 6 or some larger number, while the floral parts of Sedum are in 5's. The genus is a difficult one for the botanist, and the specific limits are very uncertain and unsatisfactory, no two authors agreeing. The key given will undoubtedly prove faulty, but is an attempt to simplify the determination of the species.

Sempervivums are mostly hardy perennials and stemless, and increase by rosettes (Fig. 3602) which are sent out from the parent plant, thereby suggesting the popular name "hen-and-chickens." The leaves are thick, short, and succulent. The flowers, which are borne in panicled cymes, are mostly yellow, greenish yellow, or some shade of rose or purple, rarely white. The individual flowers are larger than those of sedum, but the clusters are less showy. Houseleeks are cultivated more for foliage than for flowers. They are not used for as great a variety of purposes as sedums, but they are popular for carpet-bedding, rockwork, and covering dry banks and bare sandy wastes. They are of the easiest culture and are quickly multiplied by means of the offsets or rosettes. They may be used alone for permanent carpet-beds, and for this special purpose are preferable to the more popular but tender echeveria. The foliage remains green all winter. The leaves are often spotted with red toward the tip, and this color is brighter if the plants have full sunlight. The names "houseleek" and "hen-and-chickens" are loosely applied to the whole genus. If these names are to be restricted, the former should be used for Sempervivum tectorum and the latter for S. soboliferum. The common species, which grows on the roofs of houses in Europe, is S. tectorum. In the case of S. soboliferum the young rosettes are attached to the parent plant by a more slender thread than usual and more easily detach themselves and roll about. The spider-web species, of which S. arachnoideum is the commonest, are the prettiest, of them all, by reason of the webs that cover the young rosettes. These coverings are made by the plants themselves and are incidental to development, but in some species are not strongly developed and in all the group are less noticeable in the old rosettes.

S. affine, Lamotte, is offered in the trade as having dark green rosettes marked with rose: fls. red. Eu. The botanical description is not available and the species is not treated in recent European floras.—S. atropurpureum, Hort., is offered in the trade as having rosettes washed with purple: fls. red.—S. chrysanthoides, Hort., is offered in the trade as a form with white fls.—S. ciliosum, Craib. Barren rosettes more or less flat, up to 1 1/4 in. diam.: lvs. oblong-lanceolate, more or less acuminate, up to 3/4 in. long, keeled beneath, conspicuously long white-ciliate toward the apex, pubescent above, outer lvs. red-tinted; cauline lvs. imbricate, tip red-suffused: fl.- sts. about 2 in. high, bearing about 6 subsessile fls.: fls. about 1 in. across, pale green, 9-11-merous; calyx-segms. oblong-lanceolate, acute, glandular-pubescent; petals linear, glandular-pubescent externally. Hab.(?). Grown in botanic gardens.—S. colchicum, Hort., is offered in the trade.—S. commutatum, Hort., is offered in the trade.—S. Delpontii, Hort., is a trade name.—S. elegans, Lagg. Rosettes small, about 1/2 in. diam., the young ones on short shoots forming a mat: lvs. linear-lanceolate, cuspidate, short-villous, weakly cobwebbed, pale green, slightly ciliated: cauline lvs. numerous, slightly separated, oval-lanceolate, brown toward their tip and tufted ciliate: fl.-st. weak, almost prostrate on the ground during flowering and glandular-hairy; petals oval-lanceolate, acuminate. Switzerland. Not treated in any of the recent Swiss floras but offered in the trade.—S. hispanicum, Willd., is a doubtful species with subulate, semi-terete, ciliate, imbricated lvs.; possibly a Sedum.—S. hispanicum, Pourr., equals Sedum nicaeense.—S. hispidulum, Hort., is offered in the trade.—S. hispidum, Hort., is a horticultural name.—S. humilum, Hort., is a horticultural name.—S. kopaonikense. Panc., is said to be related to S. Heuffelii by Pancic, but is not well known and it is suggested that it is only a form of that species by recent authors. Serbia.—S. Laggei, Hort., is presumably an error for Laggeri.—S. leucanthemum, Hort., is probably an error for leucanthum.—S. leucanthum, Panc., is described as a form with rather small rosettes, 12-merous fls. and white petals, grown in gardens, now questionably referred to S. tectorum.-S. marginatum, Hort., is offered in the trade.—S. pilosum, Hort., is a trade name.—S. pyrenaicum, Lamotte, is offered in the trade as having handsomely formed and dark red rosettes. Eu. The botanical description is not available and the recent European floras do not treat this species.—S. rubens, Hort., is offered in the trade.—S. rubrum, Hort., is offered as having a dark base to the lvs., possibly the same as S. tectorum var. rubrum.—N. rupestre, Hort., is a trade name, perhaps a form of S. tectorum.—S. Scherzerianum, Hort., is offered in the trade.—S. speciosum, Lamotte, is offered in the trade. Eu. The botanical description is not available and none of the recent European floras mentions it.—.S. spinosum, Hort., is a trade name.—S. spinulifolium, Hort., is offered in the trade and also occurs in botanic gardens.—S. Thomsonii, Lindsay (S. arachnoideum X S. tectorum), is offered in the trade; no description of the hybrid is available.—S. umbicilum, Hort., is a trade name. Var. spinosum, Hort., is a trade name perhaps the same as the plant offered in the trade as S. spinosum.—S. urbicum, C. Smith. Shrubby: st. erect, 3 ft. high, simple, stout, covered with lf.-scars: lvs. many, rosulate at the top of the st., 4-6 x 1 1/2 in., narrowly spatulate, cuspidate, very thick, pale green, margins erosely serrulate, sessile or short-petioled: panicle very large, pyramidal, 3 ft. high and nearly as broad, many-branched; fls. 10-merous, pale yellow, 3/4 in. across; calyx cup-shaped; petals lanceolate, acute. Canary Isls. B.M. 7893. Belongs to the same group as S. arboreum. A very showy species but tender.—S. violaceum, Hort., is offered in the trade; possibly the same as S. tectorum var. violaceum.—S. Zelebori, Schott. Barren rosette more than 2 in. diam., the young ones borne on densely puberulent peduncles: lvs. spatulate-oblanceolate to spatulate-lingulate, apex apiculate and purple, short-ciliate, both surfaces densely puberulent, glaucous; cauline lvs. smaller, linear-lingulate, apiculate and puberulent: fl.-st. minutely glandular and densely hirsute: fls. 11-12-merous, pale yellowish: calyx-segms. lanceolate: petals linear-lanceolate, acuminate, viscid hirtellous dorsally. Serbia. By some authorities referred to S. Pittonii, by others to S. globiferum; apparently distinct from both of them. CH


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