Streptanthus polygaloides |
Streptanthus vernalis |
|
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milkwort jewelflower |
early jewel-flower |
|
Habit | Annuals; (sometimes glaucous), glabrous throughout. | Annuals; glabrous throughout. |
Stems | unbranched or branched distally, (0.8–)2–8(–10) dm. |
unbranched or branched distally, 0.2–2 dm. |
Basal leaves | (soon withered); rosulate; petiolate; blade 1- or 2-pinnatifid (with broadly linear to filiform lobes), 2–20 cm, margins sinuate-dentate. |
(soon withered); not rosulate; shortly petiolate; blade (fleshy), broadly obovate to suborbicular, 1.5–4 cm, margins coarsely dentate. |
Cauline leaves | blade linear, 1–10 cm × 1–3 mm, (smaller distally), base auriculate, margins entire. |
blade ovate to oblong, 0.5–1.8 cm × 1–7 mm, (much smaller distally), base auriculate to amplexicaul, margins entire. |
Racemes | ebracteate, (lax). |
ebracteate, (lax, sometimes secund). |
Flowers | (markedly zygomorphic); calyx urceolate; sepals greenish yellow or purplish, (abaxial broadly ovate, not keeled, 4–6 × 3–4 mm, lateral ovate-lanceolate, keeled, 4–6 × 1.5–2 mm, adaxial suborbicular to broadly ovate-cordate, forming a bannerlike hood, keeled, 4–6 × 6–8 mm); petals white (with brownish veins), 5–8 mm, blade 1–3 × 0.7–1.2 mm, margins crisped (channeled), claw 4–5 mm, wider than blade; stamens in 3 unequal pairs; filaments: abaxial pair (distinct), 4–5 mm, lateral pair 3–4 mm, adaxial pair (connate), 5–6 mm; anthers: abaxial and lateral pairs fertile, 1.5–2 mm, adaxial pairs sterile, 0.3–0.7 mm; gynophore 0.1–0.4 mm. |
calyx urceolate; sepals (erect), green, (ovate-lanceolate), 5–7 mm, keeled, (apex recurved); petals white, 6.5–8 mm, blade 1.5–2 × ca. 1.5 mm, margins not crisped, claw 5–6 mm, about as wide as blade; stamens in 3 unequal pairs; filaments: abaxial pair (connate 1/2 their length), 3–4 mm, lateral pair 1.5–2.5 mm, adaxial pair (connate their whole length, usually recurved), 6–8 mm; anthers: abaxial and lateral pairs fertile, 1.5–2 mm, adaxial pairs sterile, ca. 0.7 mm; gynophore 0.2–0.5 mm. |
Fruiting pedicels | strongly recurved, 2–5 mm. |
divaricate-ascending, (straight), 1–2 mm. |
Fruits | pendent, smooth, straight, flattened, 2.4–5.6 cm × 1.2–1.7 mm; valves each with obscure or somewhat prominent midvein; replum straight; ovules (10–)18–50 per ovary; style 0.8–2 mm; stigma entire. |
divaricate-ascending, torulose, straight, flattened, 3–5 cm × 1.5–2 mm; valves each with obscure midvein; replum constricted between seeds; ovules 16–20 per ovary; style 0.1–0.2 mm; stigma entire. |
Seeds | oblong, 1.7–2 × 0.9–1.1 mm; wing 0.2–0.3 mm wide, distal. |
oblong, 1.6–2 × 1–1.2 mm; wing 0.1–0.2 mm wide, distal. |
2n | = 28. |
|
Streptanthus polygaloides |
Streptanthus vernalis |
|
Phenology | Flowering May–Jul. | Flowering Mar–May. |
Habitat | Serpentine substrates in grasslands, openings chaparral, oak and pine woodlands | Serpentine talus and gravel |
Elevation | 200-1900 m (700-6200 ft) | ca. 600 m (ca. 2000 ft) |
Distribution |
CA
|
CA |
Discussion | Streptanthus polygaloides is highly variable in plant height, flower color, fruit size, and dissection of basal leaves. Further studies may lead to recognition of infraspecific taxa. The species is distributed in Butte, Calaveras, El Dorado, Fresno, Mariposa, Nevada, Sierra, Tuolumne, and Yuba counties. Streptanthus polygaloides is one of the few nickel hyperaccumulators in the flora area, and it averages 2,430–18,600 µg/g dry weight (R. D. Reeves et al. 1981; A. R. Kruckeberg and Reeves 1995). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Streptanthus vernalis, which is known from the Three Peaks in Lake County, is most closely related to S. brachiatus and S. morrisonii. All three species have the replum constricted between the seeds, a feature not known elsewhere in Streptanthus. They also have auriculate-amplexicaul middle and distal cauline leaves, torulose fruits, urceolate calyces with keeled sepals, fruiting pedicels rarely to 4 mm, and connate median filaments. Streptanthus vernalis is distinguished from the other two by being annual (versus biennial), without (versus with) basal rosettes, and having non-mottled (versus mottled) basal leaves, green (versus rose-purple, violet, or yellowish) sepals, petals without (versus with) darkly veined blades, and fewer (16–20 versus 22–38) ovules per ovary. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 720. | FNA vol. 7, p. 722. |
Parent taxa | Brassicaceae > tribe Thelypodieae > Streptanthus | Brassicaceae > tribe Thelypodieae > Streptanthus |
Sibling taxa | ||
Synonyms | Microsemia polygaloides | |
Name authority | A. Gray: Proc. Amer. Acad. Arts 6: 519. (1865) | R. O’Donnell & R. W. Dolan: Madroño 52: 202, fig. 1. (2005) |
Web links |