5 86 
SEMELE 
in the axils of scale-leaves. Firs, in little cymes (cf. Asparagus) on the 
edges of the phylloclades. The new shoots rise from the soil, and grow 
to a considerable length before the lateral branches, bearing the phyl- 
loclades, begin to unfold. 
Sempervivum Rupp, ex Linn. Crassulaceae. 50 sp. mts. of S. Eur., 
Himal., Abyss., &c. S. tectorum L., the houseleek, often planted on 
cottages to keep the slates in position, is a xerophyte with fleshy 
leaves and much vegetative multiplication by offsets. 
Senebiera DC. ( Coronopus Rupp.). Cruciferae (11. 5). 12 sp. sub- 
trop. ; one naturalised in Brit. .S’, didyma Pers. 
Senecio (Tourn.) Linn. (incl. Cacalia Linn., Cineraria Linn., Klehiia 
Haw., Ligularia Cass., &c.). Compositae (vm). 1250 sp. cosmop. 
9 in Brit, (ragwort, groundsel, &c.). The genus includes plants of 
the most various habit. Some are climbers, e.g. S. macroglossus DC. 
(S. Afr.), which is remarkably like ivy in habit. Many are xero- 
phytes, some with fleshy leaves, others with fleshy stems, others with 
hairy or inrolled leaves (cf. Empetrum). The firs, of S. vulgaris L. 
(groundsel) are regularly self-fertilised, and are very inconspicuous ; 
there are no ray-florets. In S. Jacobaea L. (rag- wort) there are 
ray- florets, and the conspicuous firs, are largely visited by insects. 
A very interesting sp. is S. (K.) articulatus Sch. Bip. (S. Afr.), 
whose fleshy stems easily separate at the joints and grow into new 
plants. 
Sequoia Endl. ( Wellingtonia Lindl.) Coniferae (Arauc. 1 c.; see C. for 
genus characters). 2 sp. N. W. Am. S. giga?itea Lindl. et Gord is the 
mammoth tree of Calif., discovered in the Sierra Nevada in 1850. 
Some specimens are more than 300 feet high and 36 feet thick, larger 
even in size than Eucalyptus ; the age of the largest is about 1 500 
years. In some museums in Brit, there are sections of a tree cut down 
in 1882 and showing 1335 annual rings. S. sempe 7 ~uirens Endl., the 
redwood, is also a gigantic tree, and is valued for its timber &c. 
Serapias Linn. Orchidaceae (3). 5 sp. Medit. 
Sericocarpus Nees. Compositae (in). 5 sp. U. S. 
Serjania Plum, ex Schum. Sapindaceae (1). 172 sp. trop. and subtrop. 
Am. Lianes with watch-spring tendrils and stip. leaves. Fruit a 
3-winged schizocarp. 
Serratula Dill, ex Linn. Compositae (xi). 40 sp. Eur. to Japan. S. 
tinctoria L. (saw-wort) in Brit. ; it is dioecious. 
Serruria Salisb. Proteaceae (1). 50 sp. S. Afr. 
Sesamum Linn. Pedaliaceae. 12 sp. trop. Afr., As. S.indicum L. 
is largely cultivated in India &c. for the oil expressed from its seeds 
(gingili, gingelly, sesame, &c.). 
Sesbania Scop. Leguminosae (111. 6). 20 sp. trop. and subtrop. S. 
aculeata Poir. is a marsh plant, giving off floating roots from the base 
of the stem, covered with a spongy aerenchyma (p. 161, and cf. 
Neptunia). 
