P0LYP0DIU3I, PRENAXTHES. 
3S3 
Exotic. 
fagop'yrum , (buck-wheat, r-w. Ju. ©.) stamens 8: styles 3: racemes pani- 
cled : leaves heart-sagittate : stem erectish, unarmed : angles of the seeds 
equal. 1 — 2 f. 
21—1. POLYPODIUM. 55. 5. 
r ulga're, (polypod. 0. Ju. 7J-.) frond deeply pinnatifid ; divisions lance-linear, 
obtuse, crenuiate, approximate, upper ones gradually smaller : fruit dots sol- 
itary : root chaffy. 8 — 12 i. -S’. 
21—2. POLYTRICHUM. 56. 4. 
juniper i'num, (hair-cap moss. O. M. %.) stem generally simple : leaves lance- 
linear, entire, flatlish, somewhat spreading : the apophysis depressed. In 
dry woods, &c. 
6—1. POXTEDERIA. 6. 17. 
corda'ta, (pickerel weed. O. b. Ju. Ij..) leaves heart-oblong, obtuse: spike ma- 
ny-flowered, compact : divisions of the corolla oblong. Yar. angustifolia, 
leaves elongated-triangular, truncate and sub-cordate at the base. 1 — 2 f. 
20—8. POPULUS. 50. 99. 
tremulo'ides, (white poplar, american aspen. E. Ap. b>.) leaves heart-roundish, 
abruptly acuminate : tooth-serrulate, glabrous, a little pubescent at the 
mare-in, with two glands at the base on the upper side : petioles compressed, 
in the young state silky. 20 — 30 f. 
Exotic. 
dilata'ta, (lombardy poplar, italian popiar, Ap. lj.) leaves glabrous both sides, 
acuminate, serrate, deltoid, the breadth equal to or exceeding the length : 
branches erect, close to the stem. It is said no pistillate plant of this spe- 
cies has been brought to America. Consequently no seeds are obtained 
from it, and it has not been re-produced here from seed. 40 — 80 f. 
12—1. PORTULACCA. 54. 86. 
olera'cea, (purslane. O. y. J. O.) leaves wedge form : flowers sessile. S. 
11—13. POTENTILLA. 35. 92. 
Leaves digitate in Jives, rarely in sevens, 
canaden'sis, (common five-finger. O. y. M. 7J..) procumbent, sub-ramose, whi- 
tish-silky: stipules ovate, gashed: leaves wedge-obovate, gash-toothed: 
stem ascending and creeping, hirsute : peduncles solitary, elongated : di- 
visions of the calyx lance-linear : petals orbicular, sub-entire, of the length 
of the calyx. This plant is so long in flower, and assumes so many forms 
and sizes, that students in botany often make several species of it. 2 — 
18 i. S. 
argen"tea, (silver five-finger. O. w-y. Ju. 7J..) stem prostrate and ascending, 
rarely sub-erect, branching, white-downy : stipules ovate-acute ; leaves 
wedge-form, gash-toothed, silvery white down beneath: petals retuse, 
scarcely longer than the calyx. 4 — 10 i. S. 
Leaves moie or less pinnate. 
anseri'na, (tansey cinquefoil. O. y. J. 7|_.) creeping : leaves interruptedly pin- 
nate, numerous, gash-serrate, silky, white-downy beneath : peduncles soli- 
tary, 1-flowered. 
19—13. POTERIUM. 5-1. 92. 
Exotic. 
sanguisor' ba, (burnet. J. 7J..) stem somewhat angled, unarmed : leaves pin- 
nate ; leafets serrate : flowers in heads. 
17—1. PREXAXTHES. 49.53. 
alba, (white lettuce. O. w. p. Au. T|~) radical leaves angled, hastate, toothed, 
