HEVEA 
423 
Heritiera (Dryand.) Ait. Sterculiaceae. 4 sp. palaeotrop. coasts. 
Hermannia Linn. (excl. Mahernia Linn.). Sterculiaceae. 120 sp. trop. 
and sub-trop., chiefly Afr. 
Herminiera Guill. et Perr. Leguminosae (in. 7). 1 sp. trop. Afr., 
H '. elaphroxylon G. et P. The wood is as light as elder pith and is 
used for floats, canoes, &c. This phenomenon seems to be related to 
the development of aerenchyma seen in other marsh plants (cf. Lyco- 
pus, Jussieua, &c., and see p. 161). H. is united to Aeschynomene 
in Nat. PJi. 
Eerminium Linn. Orchidaceae (3). 4 sp. temp. Eur., As. ( H \ 
Monorchis R. Br., musk-orchis, in Brit.) Fir. like that of orchis, 
but smaller, and fertilised by small flies which get the pollinia stuck 
to their legs. 
Hemandia Plum, ex Linn. Hernandiaceae. 8 sp. trop. (Laurineae 
Benth. -Hooker). 
Hernandiaceae. Dicotyledons (Archichl. Ranales). 4 gen. with 24 sp. 
trop. Like Lauraceae, to which they are united by Benth. -Hooker 
and Warming, but with epigynous fir. Ovary inf., i-loc., with 1 
pendulous anatropous ovule. See Nat. PJI. for details. 
Herniaria (Tourn.) Linn. Caryophyllaceae (11. 4). 15 sp. Medit., 
Eur., S. Afr. ( H . glabra L., rupture- wort, in S.W. England.) Fir. 
apetalous. 
Herpestis Gaertn. (Bacopa Aubl.) Scrophulariaceae (11. 8). 50 sp. 
trop. and sub-trop., chiefly Am. 
Eesperantha Ker-Gawl. Iridaceae (ill). 20 sp. S. Afr. 
Hesperis Linn. Cruciferae (iv. 19). 24 sp. Eur., Medit.; (1 Brit.). 
Heteranthera Ruiz et Pav. Pontederiaceae. 10 sp. trop. and sub-trop. 
Am., Afr. Leaves of two types — linear submerged and orbicular 
floating. Some have cleistogamic flrs. 
Heterocentron Hook, et Arn. = Heeria Schlecht. 
Heteromerae (Benth.-Hooker). The 2nd series of Gamopetalae (p. 135). 
Heteropteris H. B. et K. Malpighiaceae (1). 90 sp. trop. Am., 1 in 
trop. Afr. Fruit a samara (cf. Acer, Banisteria). 
Heterotoma Zucc. Campanulaceae (ill). 4 sp. Mexico. 
Heterotropa Morr. et Dcne. = Asarum Linn. 
Heuchera Linn. Saxifragaceae (1). 24 sp. N. Am. Firs, sometimes 
apetalous. 
Hevea Aubl. Euphorbiaceae (a, ii. 3). 10 sp. or more trop. Am. 
H. brasiliensis Miill.-Arg. is the source of the best caoutchouc (Para 
rubber), largely exported from Brazil. The tree was introduced into 
Ceylon and the east in 1876, and in recent years a very large planting 
industry has grown up in it, and it bids fair to supplant the wild 
rubber, as was the case with cinchona. Incisions, either herring- 
bone-like, spiral, or in large Ys at the base of the tree, are made in 
the bark, and the latex flows from them. The wound is renewed at 
intervals of a week or so by shaving off a thin slice from the lower 
