NYMPH^A-ORCHIS. 
NYMPHiEA. 12 — 1. iPapaveraceca.') [From numpha, water-nymph.] 
odora^ta, (pond-lily, w. Ju. %.) leaves round-cordate, entire, sub-em argin ate ; 
lobes spreading asunder, acuminate, obtuse; petals equalling the 4-leaved 
calyx ; stigma 16-20-rayed ; flowers large, odorous. The Egyptian lotus 
belongs to this genus. 
NYSSA. 20-5. (^liagni.) 
midtiftoWa, (sour or black gum, j-g. M. Pj.) leaves lanceolate, very entire^ 
acute at each end ; the petiole margined, and midrib villose ; fertile pe- 
duncles many-flowered; flowers in umbellate clusters; drupe nearly round^ 
dark blue. Low woods. 30-50 f. 
bifio'ra, (tupelo-tree, swamp horn-bean,) leaves ovate-oblong, very entire,, 
acute at each end, smooth ; fertile peduncles S-flowered ; drupe oTal, com- 
pressed. Swamps. 30-50 f, 
OBOLARIA. 13—2. (Pedicular cs.) 
virgin"ica, (penny-wort, r. Ap. %.) stem simple ; leaves oblong, truncate 
fleshy, purple beneath ; flowers axillary, solitary, sessile. 3-4 i. 
OCYMUM. 13—1. iLabiatcB.) [From o/«ms, swift, on account of its rapid growth.] 
basW'icum, (basil, ©.} leaves ovate, glabrous; calyx ciliate. 6-12 i. 
CENOTHERA. 8—1. (Onagrcs.) 
Capsules elongated, sessile, 
bien"nis, (scabish, tree-primrose, y. J. cf.) stem villose, scabrous; leave* 
lance-ovate, flat-toothed ; flowers sub-spiked, sessile ; stamens shorter than 
the corolla. 3-5 f. 
parvijlo'ra, (y. Ju. (^A stem smooth, sub-villose ; leaves lance-ovate, flat ; sta- 
mens longer than tne corolla. 
grandifio'ra, (y. Ju. (^.) stem nearly smooth, branched; leaves ovate-lanceo- 
late, glabrous ; flowers axillary, sessile, large ; petals obcordate ; stamens 
declining, shorter than the corolla. 2-3 f Introduced. 
Capsules obovate, davate, angular, mostly pedicelled. 
frutico'sa, (shrubby Oenothera, sun-drop, y. Ju. Q4-.) pubescent ; stem branching 
from the base, aivaricate; leaves sessile, lanceolate, acute^ slightly toothed,, 
pilose ; flowers in a terminal raceme ; petals broad-obcordate. Shady 
woods. Stem 12-18 inches high, purple. Var. ambigua, has smaller flowers. 
hybri'da, stem erect, villose; leaves pubescent on both sides, lanceolate, re- 
motely toothed, undulate; capsules somewhat spiked; flowers pale yellow. 
9-18 i. 
chrysan"tha, (dwarf-scabish,) stem slender, minutely pubescent ; leaves lan- 
ceolate, rather obtuse, fiat, entire; segments of the calyx twice as long as 
the tube ; capsule sessile ; flowers small, bright yellow. Mountains. 
OLEA. 2 — 1. iJasminecR.') [Name from the Celtic word olea, signifyiiig oil.] 
america'na, (American olive, w. M. T7.) leaves lanceolate-elliptic, entire; ra- 
cemes compressed ; bracts all persistent, connate, small. S. 
europe'a, leaves lanceolate, entire ; racemes axillary, crowded. The drupes 
when green are used for pickles, when ripe they afford the oil called olive 
oil. Ex. 
ONOCLEA. 21 — 1. (Filices.) [From o«os, a vessel, and M-et/, to- close.] 
sensi'bilis, (sensitive fern, J. %..) barren frond pinnate ; fertile one doubly pin- 
nate ; stem glabrous. The leafets slowly approach each other on pressing 
the stem in the hand. 
ONOPORDON. 17—1. (CinarocephalcB.} 
acan"thium, (cotton thistle, p. Ju. (^.) calyx scaly, scales spreadmg ; leaves 
ovate-oblong, sinuate. Naturalized. Ex. 
OPLOTHECA. 15—5. {Gerania.) 
Jlorida'na, (w. Ju.) stem erect, pubescent, with tumid joints ; leaves sessile 
lance-linear, scabrous above, lanuginous beneath. 3-4 f. 
ORCHIS. 18—1. {Orchidecb.) [A name derived from the Greek.] 
spectabi'lis, (r. M. %.) lip obovate, undivided, crenate, retuse ; petals straight ; 
