THUJA 
588 
characters). 4 sp. China, Japan, N. Am., T. occidentalis L. is the 
American, T. orientalis L. the Chinese Arbor-vitae. The leaves are 
small and closely appressed to the stems, which show dorsi-ventral 
symmetry. Cones of 3 or 4 pairs of scales, the uppermost sterile and 
often united to form the columella , the lowest also often sterile. 
[Synonymy: T . dolabrata Thunb. = Thujopsis dolabrata ; T. chi - 
lensis Don = Libocedrus chilensis ; T. Doniana Hook. = L. Doniana ; 
T. tetragona Hook. =L. tetragona; T. gigantea Carr. = Libocedrus 
decurrens .] 
Thujopsis Sieb. et Zucc. Coniferae (Arauc. 2 b; see C. for genus 
characters). 1 sp. Japan, T. dolabrata Sieb. et Zucc. 
Thunbergia Retz. (incl. Meyenia Nees). Acanthaceae (hi). 72 sp. 
trop. Old World. Many are hothouse favourites. A large number 
are twiners. The bracteoles enclose the calyx and tube of the fir. 
and are often united posteriorly. 
Thuya Linn. = Thuja Linn. 
Thymelaea Tourn. ex Scop. Thymelaeaceae. 20 sp. Medit., W. As. 
Thymelaeaceae. Dicotyledons (Archichl. Thymelaeales). 38 gen. with 
550 sp., temp, and trop., esp. in Afr. Most are shrubs with entire 
alt. stip. leaves and racemose infls. Fir. usually $ , regular 4 — 5- 
merous. The receptacle is much hollowed, usually forming a deep 
tube of leafy consistence (‘calyx-tube’); outgrowths of the axis are 
sometimes found at the base of the tube round the ovary. K peta- 
loid, like the tube, usually imbricate ; C conspicuous or small or o; 
A as many or twice or half as many as sepals, inserted on the edge of 
the tube; ovary 1- or rarely 2-loc., each loc. with 1 pendulous ana- 
tropous ovule with ventral raphe; style simple. Fruit an achene, 
berry, or drupe, often enclosed in the persistent receptacle; a few 
genera have capsules. Embryo straight ; endosperm little or none. 
Chief genera * Gnidia, Thymelaea, Daphne, Pimelea. The family 
is a very natural one, but with no very close affinities. Many authors, 
eg. Benth. -Hooker, place it near Santalaceae, but it is not a typically 
apetalous family, and seems nearer to Myrtiflorae or Parietales (see 
Nat. Pfl.). Warming places it in Thymelaeinae. 
Thymelaeales. The 21st cohort of Archichlamydeae (p. 130). 
Thymelaeinae (Warming). The 17th cohort of Choripetalae (p. 137). 
Thymus Tourn. ex Linn. Labiatae (vi. 11). 80 sp. Medit., Abyss., 
Eur. T. Serpyllum L. (thyme) in Brit. The firs, are gynodicecious 
(p. 68) with marked protandry. T. vulgaris L., the garden thyme, 
is used in flavouring. 
Thyrsacanthus Nees. Acanthaceae (iv. B). 20 sp. trop. Am. 
Thyrsopteris Kze. Polypodiaceae. 1 sp. Juan Fernandez. 
Thysanocarpus Hook. Cruciferae (iv. 14). 6 sp. Calif. 
Thysanotus R. Br. Liliaceae (ill). 22 sp. Austr., S.E. As. 
Tiarella Linn. Saxifragaceae (1). 4 sp. N. temp. 
Tibouchina Aubl. Melastomaceae (1). 190 sp. trop. Am. 
