568 SECURINEGA 
Securinega Comm, ex Juss. Euphorbiaceae (A. 1. 1). io sp. temp, and 
subtrop. 
Sedum Tourn. ex Linn. Crassulaceae. 140 sp. N. temp., 1 in Peru; 
9 in Brit., incl. S. Telephium L. (orpine or livelong), S. Rhodiola DC. 
(rose-root), S. anglicum Huds. and S. acre L. (stonecrop or wall- 
pepper). Fleshy-leaved xerophytes. 
Seguieria Loefl. Phytolaccaceae. 8 sp. S. Am. Leaves leathery; 
stipules thorny. The plants have a powerful odour of garlic. Cpl. 1. 
The fruit is a samara, closely resembling one half of that of Acer or 
many Malpighiaceae. 
Selagineae (Benth. -Hooker). See Scrophulariaceae. 
Selaginella Spring. The only genus of Selaginellaceae. 350 sp. chiefly 
trop. A few are temp. e.g. S. selaginoides Link on boggy hill sides in 
Brit. Most of the sp. live in damp places, especially in forests, but 
there are a few xerophytes. The embryo is provided with a suspensor, 
and grows directly into the leafy plant, which shows a habit very 
similar to that of Lycopodium — much-branched stem, often creeping, 
bearing roots on the lower side and leaves on the upper, with 
terminal cones of sporangia. The leaves may be spirally arranged as 
in most sp. of Lycopodium (e.g. in S. selaginoides ), or more commonly 
they form 4 ranks, two outer ones of large, two inner of small leaves, 
thus giving the stem a dorsiventral structure. The roots in some sp., 
e.g. S. Kraussiana A. Br. and S. Martensii Spring, are borne on 
rhizophores , anomalous stem branches developed at the nodes and 
exhibiting a sort of intermediate structure between stem and root. 
The sporangia are placed at the bases of the leaves in terminal cones, 
which exhibit radial symmetry. The mega-sporangia contain 4 large 
spores and can easily be distinguished by the naked eye from the 
micro-sporangia. On germination a microspore produces a rudimen- 
tary male prothallus bearing an antheridium. The megaspore forms a 
female prothallus, which remains enclosed in the burst spore, and has 
an upper small-celled green portion and a lower large-celled storage 
portion as in Salviniaceae &c. 
A. lepidophylla Spring is a curious little xerophyte which curls up 
into a ball in the dry season, and may be rolled about by the wind 
(compare Anastatica). 
Selaginellaceae. Lycopodinae (Heterosporous). Only genus Selagi- 
nella (q.v.). 
Selago Linn. Scrophulariaceae (11. 9). 80 sp. S. Afr., Madagascar. 
Selenipedium Rchb. f. Orchidaceae (2). 2 sp. Panama, Guiana. Like 
Cypripedium, but ovary 3-loc. 
Selinum Linn. Umbelliferae (6). 25 sp. N. Hemisph., S. Afr. 
Selliera Cav. Goodeniaceae. 2 sp. Austr. 
Semecarpus Linn. f. Anacardiaceae (iv). 40 sp. Ceylon to Austr. 
Semele Kunth. Liliaceae (vn). 1 sp. Canaries, S. androgyna Kunth 
(Ruscns androgynus L.). A climbing shrub with leaf-like phylloclades 
