382 PISUM, POLYGONUM. 
16—10. PISUM. 32. 93. 
Exotic. 
cati'vum, (pea, p. w. J. ©.) petioles terete : stipules round and crenate at the 
base : peduncles many-flowered. Var. umbcllatum, (boquet pea,) has the 
stipules 4-cleft, acute. Var. quadratum, (quadrate pea,) fruit ash-colour, 
4-sided. Var. humile, (dwarf pea,) stem erect, not climbing : leafets round- 
ish. 
4—1. PLANTAGO. 54. 31. 
major , (plantain. O. w. J. 7J..) leaves ovate, sub-dentate, sub-glabrous : scape 
terete : spike oblong, imbricate. 6 — 24 i. S'. 
20—13. PLATANUS. 50. 99. 
occldenta"lis, (button wood, american plane-tree, false sycamore. O. J. fj.) 
leaves quinquangular, obsoletcly lobed, toothed; pubescent beneath : stem 
and branches becoming white. Grows to a greater size than any other tree 
in America. 
3—2. POA. 4. 10. 
Remarks. The word poa is pure Greek, and signifies pasture or fodder. 
Linnaeus applied the name to this genus, because it includes the most com- 
mon pasture grass and meadow grass. The poa pratensis, aided by the ag- 
rostis vulgaris, constitutes most of those beautiful carpets which cover our 
fields, lawns, and road-sides. 
an"nua , (Ap. ©.) panicle sub-secund, divaricate : spikelets ovate-oblong, 5- 
flowered : florets free : culm oblique, compressed : root fibrous. 6 — 8 i. S. 
praten"sis , (O. J. 7|..) panicle diffuse: upper leaves much shorter than ,the 
the smooth sheaths : florets acute, 5-nerved, webbed at the base : stipule 
short truncate : root creeping. 2 — 3 f. S'. 
12—1. PODOPHYLLUM. 27. 61. 
pelta'tum, (wild mandrake, may-apple. O. w. M. 2J..) stem terminated with 2 
peltate palmate leaves : flower single, inserted in the fork, formed by the 
petioles of the leaves. Sometimes the plant is 3-leaved, and sometimes the 
flower is inserted on the side of one of the petioles. 1 — 2 f. S'. 
18—1. POGONIA. 7. 21. 
ophioglosso'ides, (snake mouth arethusa. O. r. Ju. 7)..) root fibrous : scape with 
2 distant leaves, 1 or 2-flowered : leaves, lance-oval : lip fringed. 8 — 12 
i. S. 
G— 1. POLYANTHES. 10. 17. 
Exotic. 
tubero'sa, (tuberose. %■) flowers alternate, in pairs : rootlets tuberous : scape 
scaly : leaves linear, long. Sweet scented. 
16— G. POLYGALA. 33. 35. 
paucifo'lia, (flowering wintergreen. O. r. M. % ) small, large-flowered : stem 
simple, erect, naked below : leaves ovate, acute, glabrous, near the top of 
the stem : flowers crested, terminal, about in threes. 3 — 4 i. S. 
sen"cga, (seneca snake-root, mountain flax. O. r. or w. J. I;.) stem erect, sim- 
ple leafy : leaves alternate, lanceolate : spike terminal filiform : flowers 
alternate, not crested. Var. albida, leaves lanceolate or oval : spike some- 
what crowded : flowers white, sub-sessile. 8 — 14 i. S. 
poly^'ama, rubella of wildenow, (ground flower. O. p. J. %.) stems numerous : 
leaves linear-oblong, alternate downwards : racemes terminal and lateral, 
elongated ; flowers sessile : radical racemes procumbent, with apterous flow- 
ers. 4 — 8 in. 
8—3. POLY GONUM. 12. 28. 
ax ncula're, (knot-grass. O. w. M. %.) stamens 8, styles 3 : leaves lanceolate, 
scabrous at the margin : stipules short, lacerate : stem procumbent : flow- 
ers sub-sessile, axillary, minute. 6 — 12 i. S. 
