Lithophragma

Illustrator: Yevonn Wilson-Ramsey

Copyright: Flora of North America Association

Herbs, rhizomatous, not stoloniferous; caudex sometimes bearing bulbils. Flowering stems erect, leafy, 8–85 cm, stipitate-glandular. Leaves in basal rosette and cauline; cauline leaves (1–)2(–10), usually alternate (opposite in L. cymbalaria), unlobed, lobed, or palmately compound, sometimes with bulbils in axils; stipules present; petiole stipitate-glandular; blade rhombic or orbiculate to reniform, lobed, base cordate, hastate, rounded, ligulate, or cuneate, ultimate margins entire or toothed, apex obtuse or acute, surfaces often stipitate-glandular; venation palmate. Inflorescences compact or lax racemes, arising from axillary buds in basal rosette, 2–12(–25)-flowered, sometimes flowers solitary, (flowers sometimes replaced by bulbils), bracteate. Flowers: hypanthium partially adnate to proximal 1/2 to entire length of ovary, free from ovary 1–2 mm, green; sepals 5, green tinged with red; petals 5, white or pink; nectariferous tissue inconspicuous; stamens 10, (inserted on hypanthium, inner whorl attached proximal to point of petal insertion); filaments filiform; (anthers cordate); pistil 3-carpellate; ovary superior to 1/2 or almost completely inferior, 1-locular, carpels fully connate at ovaries; placentation parietal; styles 3; stigmas 3. Capsules 3-beaked. Seeds (50–200), usually dark brown, ovoid, smooth, wrinkled, or tuberculate. x = 7.

Distribution

w North America.

Discussion

Tellima R. Brown [unranked] Lithophragma Nuttall, J. Acad. Nat. Sci. Philadelphia 7: 26. 1834 (as Lithofragma); Pleurendotria Rafinesque, name rejected

Species 10 (10 in the flora).

Selected References

Kuzoff, R. K., D. E. Soltis, L. Hufford, and P. S. Soltis. 1999. Phylogenetic relationships within Lithophragma (Saxifragaceae): Hybridization, allopolyploidy, and ovary diversification. Syst. Bot. 24: 598–615.

Kuzoff, R. K., L. Hufford, and D. E. Soltis. 2001. Structural homology and developmental transformations associated with ovary diversification in Lithophragma (Saxifragaceae). Amer. J. Bot. 88: 196–205.

Taylor, R. L. 1965. The genus Lithophragma (Saxifragaceae). Univ. Calif. Publ. Bot. 37: 1–122.

Lower Taxa

Lithophragma affine, Lithophragma bolanderi, Lithophragma campanulatum, Lithophragma cymbalaria, Lithophragma glabrum, Lithophragma heterophyllum, Lithophragma maximum, Lithophragma parviflorum, Lithophragma tenellum, Lithophragma trifoliatum

Key

1	Leaves palmately compound, 3-foliolate; seeds spiny.	Lithophragma maximum
1	Leaves unlobed or lobed, or 3-foliolate; seeds smooth, wrinkled, tuberculate, or rough	> 2
2	Stigma papillae in narrow subapical band; seeds smooth or wrinkled	> 3
2	Stigma papillae covering apical surface; seeds tuberculate, tubercles in 3-19 rows, blunt or spinelike	> 6
3	Leaf blades light green; cauline leaves 3-lobed, appearing pinnatifid; flowers persistent, slightly pendulous; racemes erect; petals 5-7-lobed; ovaries to 1/2 inferior.	Lithophragma tenellum
3	Leaf blades dark green or reddish green; cauline leaves 3-foliolate or 3-lobed; flowers deciduous if unfertilized, horizontal; racemes often lax, nodding; petals 3-lobed; ovaries 1/2+ inferior	> 4
4	Hypanthia elongate-obconic, length 3-4 times diam.; petals pink; flowers fragrant.	Lithophragma trifoliatum
4	Hypanthia obconic to obconic-elongate, length 2 times diam.; petals usually white, sometimes pink; flowers not fragrant	> 5
5	Cauline leaves 3-foliolate; hypanthia obconic-elongate; petals white or pink, often with prominent venation, 3-lobed, obovate-rhombic, widely spreading, ultimate margins entire; ovaries 1/2+ inferior.	Lithophragma parviflorum
5	Cauline leaves 3-lobed; hypanthia obconic; petals white with obscure venation, usually shallowly 3-lobed, ovate-elliptic, not widely spreading, ultimate margins sometimes with extra tooth, (lobes acute); ovaries ± completely inferior.	Lithophragma affine
6	Cauline leaves opposite (1 pair); flowering stems simple; petals unlobed, without serrations at base, ultimate margins entire.	Lithophragma cymbalaria
6	Cauline leaves alternate; flowering stems often branched; petals lobed or, if unlobed, margins sometimes with serrations at base	> 7
7	Hypanthia broadly campanulate; flowers pendulous, petals partly included, ovate-elliptic, ultimate margins lacerate; flowers ± sessile.	Lithophragma campanulatum
7	Hypanthia narrowly campanulate; flowers horizontal, petals completely exserted, obovate-pandurate, ovate-elliptic, or ovate and palmately 5-lobed, ultimate margins entire; flowers long-pedicellate	> 8
8	Hypanthia with truncate base; petals white, simple or 3-7-lobed; flowers not fragrant; racemes lax, nodding; cauline leaves 2-10; ovaries superior.	Lithophragma heterophyllum
8	Hypanthia with acute, obtuse, or hemispheric base; petals white or pink, unlobed, serrately 3-5-lobed, or 5-lobed; flowers sometimes fragrant; racemes erect; cauline leaves 2-4; ovaries to 1/2 inferior	> 9
9	Plants usually robust; leaves usually unlobed or 3-5-lobed; petals white, unlobed or 3-5-lobed with serrations at base; inflorescences 2(-3)-branched, 3-5(-25)-flowered racemes, flowers rarely replaced with bulbils.	Lithophragma bolanderi
9	Plants usually fragile; leaves lobed (lobes rounded); petals usually pink, rarely white, palmately 5-lobed, base without serrations; inflorescences rarely branched (unless plant with bulbils), solitary flowers or 2-5(-7)-flowered racemes, often appearing corymbose; flowers sometimes replaced with bulbils.	Lithophragma glabrum