TIIEL YGONUM 
604 
theoretical explanation (see Eichler’s Bliithendiag .) is that each limb 
of the sympodium ends blindly, bearing 2 leaves, only one of which 
developes. In the axil of the other stands the <? infl., while in the 
axil of the developed leaf arises the ‘continuation’ shoot of the sym- 
podium, and below this, as an accessory bud, the shoot bearing the ? 
fir. P 2 — 5, A 10 — 30; in the ? an inferior ovary of 1 cpl. with basal 
style; ovule campylotropous. Fruit a drupe. The plant is used as 
spinach, but has an aperient action. 
Thelymitra Forst. Orchidaceae (4). 20 sp. Austr. The fir. is almost 
regular. Some sp. fertilise themselves in the bud, the fir. however 
afterwards expanding. 
Thelypodium Endl. Cruciferae (1. 1). 15 sp. U. S. 
Theobroma Linn. Sterculiaceae. 12 sp. trop. Am., of which T. Cacao 
L. is the most important. Its firs, are borne on the old wood, and 
give large tough berry-fruits, containing exalbuminous seeds, which 
after roasting &c., yield cocoa or chocolate. The young leaves are 
red and pendulous (p. 190). 
Theodora Medic. = Schotia Jacq. 
Theophrasta Linn. Myrsinaceae (1). 4 sp. W. Ind. The upper part 
of the stem bears thorny scales. Serial buds occur in the leaf-axils 
and ultimately cause the phenomenon of stem-flowering (p. 190), for 
firs, arise in the axils of scale-leaves on these compressed shoots. 
Thermopsis R. Br. Leguminosae (ill. 2). 15 sp. Himal. to Carolina. 
Thesium Linn. Santalaceae. 1 1 5 sp. chiefly N. temp. Old World. 
T. humifusum DC. in Brit, (bastard toad-flax). Herbaceous root- 
parasites with green leaves (see Scrophulariaceae, and p. 176). Firs. 
$ , in racemes. The bract is adnate -to the peduncle, and with the 
2 bracteoles forms a sort of involucre. P (3 — 5), tubular. Ovary 
inferior. 
Thespesia Soland. Malvaceae (iv). 4 sp. trop. As., Polynes. 
Thevetia Linn. Apocynaceae (1. 3). 8 sp. trop. Am. 
Thibaudia Ruiz et Pav. (excl. Ceratostema Juss.). Ericaceae (in. 8). 
30 sp. trop. Am., often cultivated for their firs. 
Thinouia Planch, et Triana = Thouinia Poit. 
Thismia Griff. Burmanniaceae. 6 sp. Indo-mal. Saprophytes. See 
Groom in Ann. of Bot., June 1895. 
Thladiantha Bunge. Cucurbitaceae (1). 8 sp. E. As. to Java. Climb- 
ing herbs with root-tubers. 
Thlaspi (Tourn.) Linn. Cruciferae (11. 6). 60 sp. Medit., As., N. 
Am.; 3 in Brit, (penny-cress). 
Thouinia Poit. (incl. Thinouia Planch, et Triana). Sapindaceae (1). 
25 sp. trop. Am., W. Ind. Lianes. 
Thrinax Linn. f. Palmae (1. 2). 10 sp. W. Ind. (thatch-palm). The 
leaves are used for roofing, and the plants also yield useful fibre. 
Thrincia Roth = Leontodon Linn. 
Thuja Linn. (Thuya Linn.). Coniferae (Arauc. 2 b; see C. for genus 
