TRITICUM, USNEA. 
395 
leaves longer and narrower. 12 to 18 inches high, leaves often 3 to 4 
inches broad. Peduncles about 3 inches long. 9 — 16 i. S. 
3—2. TRITICUM. 4. 10. 
Exotic. 
hyber'num , (winter wheat. J. <J.) calyx-glume 4-flowered, tumid, even, 
imbricate, abrupt, with a short compressed point ; stipule jagged : cor- 
ollas of the upper florets somewhat bearded. There are several varie- 
ties of this species which are induced by culture. 
8—1. TIIOP/EOLUM. 23. 73. 
Exotic. 
ma'jus , (nasturtion, indian cress, y. & r. Ju. ©. & 7)..) leaves peltate, sub- 
repand ; petals obtuse, some of them fringed. 
6—1. TULIPA. 10. 14. 
Exotic. 
suare'olms , (sweet tulip. M. 7J..) small stem 1 -flowered, pubescent; flower 
erect ; petals obtuse, glabrous ; leaves lance-ovate. 
gesneria'na , (common tulip. M. 71.) stem 1-flowered, glabrous ; flower vari- 
ous-coloured, erect ; petals obtuse, glabrous ; leaves lance-ovate. 
17—2. TUSSILAGO. 49. 55. 
far'fara, (colt’s foot. y. Ap. 21 .) scape single-flowered, scaly; leaves cor- 
date, angular, toothed downy beneath. The flower appears long before 
the leaves. 4 — 6 i. 
19—3. TYPHA. 3. 8. 
latifo'lia, (cat-tail, reed-mace. O. Ju. 71.) leaves linear, flat, slightly convex 
beneath: 3taminate and pistillate aments close together. Wet 4 — 6 f. S. 
5—2. ULMUS. 53. 99. 
america'na, (elm, white-elm. O. g-p. Ap. U-) branches smooth : leaves oblique 
at the base, having acuminate serratures a little hooking : flowers pedicel- 
led : fruit fringed with dense down. Yar. pendula, has hanging branches 
and smoothish leaves. 40 — 70 f. S. 
21 — 4. ULVA. 57. 2. 
lin"za , frond lance-linear ; margin undulate-crisped. About an inch broad, 
tapering to the base, green. Sea-shore. 
5—2. URASPERMUM. 45. CO. 
claylo'ni, (sweet cicely. O- J. Tj..) leaves compound, hairy : leafet3 gash-tooth- 
ed ; umbels axillary and terminal, about 5-rayed : style as long as the vil- 
lose germ, filiform, deflected. 2 f. 
21—6. UREDO. 58. 1. 
linea ris, (ycllow-grain-rust. J. ©.) linear, very long, stained-yellow, at length 
but obscurely coloured. On the culms and leaves of barley, oats, rye, 
wheat, 6i c. 
19-4. URTICA. 53. 99. 
clio'ica, (common nettle. O. J. 7]..) leaves opposite, cordate, lance-ovate, coarse- 
ly serrate: flowers dioecious ; spikes panicled, glomerate, in pairs, longer 
than the petioles. 2 — 3 f. S. 
21—5. USNEA. 57. 2. 
plica'ta, frond pendulous, smooth, pale : branches lax, very branching, sub- 
fibrous ; the extreme ones capillary : receptacles flat, broad, ciliate : the 
cilia: very slender and long. On trunks and branches of trees : most com- 
