Herbs or shrubs, with alternate opposite or verticillate leaves. Flowers racemose, spicate, or capitate, rarely solitary and axillary, sometimes also cleistogamous and subterranean.

Sepals very unequal, the two lateral ones large and petaloid. Petals 3, united into a tube which is split on the back, and more or less adnate to the stamens. Stamens 8 or 6, monadelphous below, or diadelphous; capsule membranous, compressed, dehiscent along the margin.

Seeds 1 in each cavity, generally hairy. [Greek, much milk.]

A genus of about 450 species, of wide geographic distribution. Besides the following, about 40 others occur in the southern and western parts of North America. Type species: Polygala vulgaris L.

* Flowers in corymbed spike-like racemes at the summit of the stem, yellow.

Basal leaves long, narrow, acuminate.

1.

P. cymosa.

Basal leaves spatulate, or obovate.

2.

P. ramosa.

** Flowers in solitary spikes or spike-like racemes, terminating the stem and branches.

Basal leaves spatulate, or obovate; flowers orange yellow.

3.

P. lutea.

Basal leaves inconspicuous, or wanting; flowers not yellow.

Leaves, at least the lower, verticillate; spikes 4"-9" thick, blunt; flowers purple to greenish white.

Spikes sessile, or nearly so; wings deltoid.

4.

P. cruciata.

Spikes peduncled; wings lanceolate-ovate.

5.

P. brevifolia.

Leaves verticillate and alternate; spikes 2" - 3" thick, acute.

Verticillate leaves predominating; spikes dense; flowers green to purplish.

6.

P. verticillata.

Alternate leaves predominating; spikes loose, long; flowers more purple.

7.

P. ambigua.

Leaves all alternate.

Petals united into a cleft tube, 3"-4" long; flowers pink.

8.

P. incarnata.

Petals not conspicuously united into a tube.

Spikes ovoid to globose.

Bracts persistent; flowers rose-purple to white.

Spikes blunt; wings broadly ovate.

9.

P. t'iridescens.

Spikes acutish; wings narrowly ovate or elliptic.

10.

P. Curtissii.

Bracts deciduous; flowers rose-purple.

11.

P. mariana.

Spikes cylindric.

Leaves oblanceolate to linear, 2"-6" long; flowers greenish to purplish.

12.

P.Nuttallii.

Leaves lanceolate, 1' - 2' long; flowers white or greenish.

13.

P. Senega.

Spikes elongated-conic; flowers white.

14.

P. alba.

*** Flowers distinctly racemose, rose or purple.

15.

P. polygama.

**** Flowers 1-4, large, axillary, but apparently terminal, rose-purple to white.

16.

P. paucifolia.