Manual of botany by Gray Asa

Author:Gray, Asa
Language: eng
Format: epub
Tags: Botany--United States.
Publisher: New York: American Book Co
Published: 1950-03-25T05:00:00+00:00

flowers; their parts rarely in fours. (Name a diminutive from potens, powerful, originally applied to P. anserina, from its once reputed medicinal powers.)*

a.Carpels and achenes pubescent. . . b.

fe.Shrub; leaves pinnate, with 5-7 approximate entire leaflets; petals yellow; style attached below middle of achene, enlarged upward, only slightly overtopping achene 1. P. fruticosa.

^.Herbaceous or merely suffruticose at base; leaflets 3; petals white; style filiform, prolonged.

Leaves coriaceous, evergreen; leaflets narrowly cuneate, entire except at 3-5-toothed apex; flowers in stiff terminal cymes; achenes densely

hairy; style basal 2. P. tridentata.

Leaves herbaceous; leaflets obovate to rounded-ovate, with regularly toothed margins; flowers 1-few on filiform branches; achenes sparsely

hairy; style terminal 3. P. sterilis.

a.Carpels and achenes glabrous. . . c.

c.Suffruticose, with prolonged woody stems rooting in water or marsh; leaves

not rosulate, pinnate; petals purple; disk thick and hairy; style lateral. . 4. P. palustris.

c.Herbaceous, annual or biennial, or, when perennial, often with flowering

stems arising from crowns or the crowns bearing rosettes of leaves.

. . d.

d.Glandular-villous erect perennial; leaves pinnate, with many (in ours

7-11) leaflets; petals white or creamy; stamens 25-30, in 5 groups;

style subbasal, thickened below middle 5. P. arguta.

d.Rarely if ever glandular-villous; petals yellow; stamens fewer; style borne at or well above middle of carpel. . . e. e.Style thickened at base or below the middle, slenderly conical; flowers mostly numerous (1-few in nos. 6 and 9), in cymes. . . f. /.Lower leaf-surfaces or branches of inflorescence tomentose or lanate with implexed soft hairs (rarely glabrous or glabrate in age); perennials with crowns long retaining marcescent old stipules or their remnants. . . g. gr.Style short and much thickened, shorter than to but slightly longer than mature carpel. . . h. /i.Basal leaves ternate or digitate.

Densely cespitose; basal leaves mostly ternate, with regularly toothed ovate, obovate or broadly oblong leaflets; flowers l_few, long-peduncled, 1—2 cm. broad; petals much exceeding calyx-lobes 6. P. nivea.

Loosely cespitose or with erect or ascending stems terminating in many-flowered cymes; leaflets of basal leaves 5-7, cuneate; flowers 1—1.5 cm. broad; petals shorter than to barely exceeding calyx-lobes.

Cauline and radical leaves very dissimilar, with revolute incised or irregularly toothed margins; tomentum of lower leaf-surface very dense, not mixed with long trichomes;

style papillose at base. .. 7. P. argentea.

Cauline and radical leaves similar, with flat regularly toothed margins; tomentum of lower surface sparse,

mixed with long trichomes; style epapillose 8. P. canescens.

Ti.Basal leaves pinnate.

Flowering stems 1-9 cm. long, 1 (rarely-3)-flowered. ... 9. P. ustica-

pensis. Flowering stems 1.5-5 dm. high, many-flowered.

Basal leaves oblong to oblong-obovate, very much longer

than broad, with 7-15 leaflets 10. P. pensyl-

vanica. Basal leaves suborbicular to round-obovate, with 5-7

leaflets 11. P. pectinata.

g. Style short-conic above the base, then slender and prolonged to twice or thrice length of mature carpel. . . i. t.Basal leaves pinnate, with 5-11 leaflets, the lower pairs of leaflets remote. Bractlets and calyx-lobes subequal; tomentum of leaves with

silvery-glistening hairs intermixed 12. P. Hippiana.

Bractlets much narrower and barely half as long as calyx-lobes; tomentum opaque 13. P. effusa.

* The figures show a characteristic leaf for many species, a portion of stem of a few, rhizomes of nos.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.