Perennial herbs, with short leafy caudices and solitary or clustered scapes, and basal entire or toothed leaves, the flowers in terminal compact or open compound cymes. Calyx-lobes 5, erect or reflexed. Corolla white or mainly so, essentially regular, the petals clawless or rarely clawed. Stamens 10; filaments subulate or clavate. Ovary slightly inferior, the carpels slightly united. Follicles spreading or with spreading tips. [Greek, small-flower.]

About 65 species, natives of the north temperate and boreal parts of both hemispheres. Type species: Micranthes semipubescens Haw. *

Filaments subulate or filiform-subulate; petals not yellow-blotched.

Cymules wholly or mainly aggregated into a head; follicles red.

1.

M. nivalis.

Cymules in pyramidal or corymb-like panicles; follicles green.

Corolla white; petals broad; calyx-lobes not reflexed at maturity.

Cymules permanently compact; petals not twice exceeding the calyx.

2.

M. texana.

Cymules ultimately lax; petals more than twice exceeding the calyx.

3.

M. virginiensis.

Corolla greenish; petals narrow; calyx-lobes reflexed at maturity.

4.

M. pennsylvanica.

Filaments clavate; petals yellow-blotched.

Leaves with elongated blades.

5.

M. micranthidifolia.

Leaves with short or suborbicular blades.

Leaf-blades narrowed at the base; neither cordate nor of an orbicular type.

6.

M. caroliniana.

Leaf-blades cordate at the base, orbicular or nearly so.

7.

M. Geum.

4 Micr nthes Haw Syn Pl Succ 320 1812 498

1. Micranthes Nivalis (L.) Small. Clustered Alpine Saxifrage

Fig. 2156

Saxifraga nivalis L. Sp. Pl. 401. 1753.

Micranthes nivalis Small, N. A. Flora 222: 136. 1905.

Seldom over 6' high. Scape viscid, naked, or bracted at the base of the capitate sometimes branched inflorescence; leaves ovate or oval, narrowed into a margined petiole, thick; flowers white, 3"-5" broad, in a compact cluster; calyx-lobes ovate or oblong, spreading, obtuse, about one-half the length of the oblong or oblong-ovate petals; ovary half-inferior; follicles deep purple, divergent.

Labrador and arctic America, south in the Rocky Mountains to Arizona. Also in northern and alpine Europe and Siberia. Summer. Said to flower beneath the snow.