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. rubescens Torr.

Leaf: petiole 1–15 cm; blade 8–60 mm, broadly ovate to ± round, ± deeply 5–9-lobed
Inflorescence 7–55 cm, often 1-sided, open or dense, cylindric to conic, glandular
Flower ± bilateral; part of hypanthium fused to ovary 0.9–2.5 mm, ± = long side of free part, together with calyx lobes 3–6 mm; calyx lobes generally unequal, whitish to pink-red with green tips, becoming redder; petals 3–6 mm, > calyx lobes, narrowly oblanceolate to thread-like; stamens > calyx lobes, exserted; mature styles generally >> 1.5 mm, exserted
Ecology: Dry, rocky areas
Elevation: 1500–4000 m.
Bioregional distribution: Sierra Nevada (except Tehachapi Mountain Area), Peninsular Ranges, Great Basin Floristic Province (except n Modoc Plateau), Desert Mountains
Distribution outside California: to Oregon, Idaho, Colorado, Texas, n Mexico
Highly variable. Closely related to H. parishii and H. mexicana of Mex; hybridizes with other species. Varieties intergrade. Needs monographic study
Horticultural information: DRN: 4, 5 &IRR: 1, 2, 15, 16, 17, 24 &SHD: 3, 6, 7, 14, 18, 19, 20, 21, 22, 23.