Alyssum murale

Perennials; (cespitose, sometimes caudex woody); canescent or not, trichomes stellate, 5–20-rayed. Stems often several from caudex (sterile shoots absent or few), usually erect or ascending, (2.5–)3–6(–7) dm. Cauline leaves subsessile; blade narrowly oblanceolate to linear, (0.5–)0.7–2.5(–3) cm × 1–5(–8) mm (gradually smaller distally), base cuneate to attenuate, apex obtuse to subacute, (surfaces often more grayish abaxially than adaxially). (Racemes corymbose, in panicles terminating each stem.) Fruiting pedicels divaricate-ascending, straight or slightly curved distally, slender, (2–)2.5–6(–8) mm, trichomes uniformly stellate. Flowers: sepals oblong, 1.2–2 × 0.4–0.7 mm, stellate-pubescent; petals yellow, spatulate, 2.5–3.5 × 0.5–1 mm, base attenuate, apex often obtuse or rounded, glabrous abaxially; filaments: median pairs broadly winged, apically 1-toothed, lateral pair with lanceolate or narrowly oblong basal appendage, apically subacute, 1.5–2.5 mm; anthers oblong, 0.2–0.3 mm. Fruits broadly elliptic to orbicular, 3.5–5 × 2.5–5 mm, apex obtuse to rounded; valves not inflated, flattened and slightly undulate, stellate-pubescent; ovules 1 per ovary; style (slender) 1–2 mm, sparsely pubescent. Seeds suborbicular to broadly ovoid, compressed, 3–3.8 × 2–3.2 mm, margins winged, wing 0.5–0.9 mm wide. 2n = 16, 32.

Phenology: Flowering May–Jul.
Habitat: Waste areas, roadsides
Elevation: 1500-1800 m

Introduced; Alta., B.C., Ont., Que., Colo., Oreg., Utah, Europe, sw Asia.

Discussion

Selected References

None.

Lower Taxa