SAXIFRAGACEAE

SAXIFRAGE FAMILY

Patrick E. Elvander

Perennial or subshrub from caudex or rhizome, generally ± hairy
Stem often ± leafy on lower half, rarely trailing and leafy throughout
Leaves generally simple, basal or sometimes cauline, generally alternate, generally petioled; veins ± palmate
Inflorescence: panicle, generally ± scapose
Flower generally bisexual, generally radial; hypanthium free to ± fused to ovary; calyx lobes generally 5; petals generally 5, free, generally clawed, generally white; stamens generally 5 or 10; pistils 2 and simple or 1 and compound (chambers 1–2, placentas 2–4, axile or parietal), ovary superior to inferior, sometimes more superior in fruit, styles generally 2
Fruit: 2 follicles or 2–4-valved capsule
Seeds generally many, small
Genera in family: 40 genera, 600 species: especially n temp, arctic, alpine; some cultivated (Bergenia , Darmera , Heuchera , Saxifraga , Tellima , Tolmiea )
Reference: [Soltis 1988 Syst Bot 13:64–72]

HEUCHERA

ALUMROOT

Rhizome scaly; bulblets 0
Leaves basal, sometimes a few cauline; blade ovate, base cordate to reniform, lobes and teeth shallow, irregular
Inflorescence generally raceme-like; bracts generally scale-like
Flower radial to ± bilateral; hypanthium partly fused to ovary; calyx lobes equal or not; petals 0 or 5, generally equal; stamens 5, generally equal; pistil 1, ovary > half inferior, chamber 1, placentas 2, parietal
Fruit: capsule
Species in genus: 50 species: North America
Etymology: (J.H. von Heucher, German professor of medicine, 1677–1747)
Reference: [Rosendahl, Butters, & Lakela 1936 Minn Stud Plant Sci 2:1–180]
A very difficult genus, highly variable at many levels and needing much additional research.

Native

H. micrantha Lindl.

Leaf: petiole 3–30 cm, generally glandular; blade 20–80 mm, broadly ovate to oblong, 5–7-lobed, generally hairy
Inflorescence 1–10 dm, wide to narrow, open, glandular; bracts on peduncle few, small, leaf-like
Flower radial; part of hypanthium fused to ovary 0.5–2.5 mm, generally > free part, together with calyx lobes 1–3 mm; calyx lobe tips green to red; petals 3–5 mm, 2 X calyx lobes, oblanceolate, sometimes ± pink; stamens > calyx lobes, exserted; mature styles 2–4 mm, exserted
Chromosomes: 2n=14
Ecology: Moist, rocky banks and cliffs
Elevation: < 2500 m.
Bioregional distribution: Northwestern California, Cascade Range, Sierra Nevada, Central Western California (except Inner South Coast Ranges)
Distribution outside California: to British Columbia, Idaho
Highly variable. Plants from SN, CaR with petioles minutely glandular, upper surface of leaf blade glabrous may be called var. erubescens (A. Braun & P.C. Bouché) Rosend. Plants from NW, w CW with petioles densely glandular, upper surface of leaf blade hairy may be called var. hartwegii (Wheelock) Rosend
Synonyms: var. pacifica Rosend., Butters & Lakela
Horticultural information: IRR, DRN: 2, 4, 5, 6, 17, 24 &SHD: 1, 3, 7, 8, 9, 10, 14, 15, 16, 18, 19, 20, 21, 22, 23; GRCVR; CVS.