Alyssum
Family: Brassicaceae
Alyssum image
  • FNA
  • Gleason & Cronquist
  • Resources
Ihsan A. Al-Shehbaz in Flora of North America (vol. 7)
Annuals or perennials [biennials, subshrubs]; not scapose; trichomes sessile, stellate, with 2-6 minute basal branches (branches as many as 3-25), rays branched or not, sometimes trichomes simple [lepidote]. Stems erect, ascending, or decumbent, unbranched or branched. Leaves basal and cauline; petiolate or sessile; basal rosulate or not, petiolate or sessile, blade margins entire; cauline petiolate or sessile, blade (base cuneate or attenuate), margins entire. Racemes (few- to several-flowered, sometimes corymbose or paniculate). Fruiting pedicels ascending, divaricate, or reflexed, slender or stout. Flowers: sepals ovate or oblong, lateral pair not saccate; petals yellow or white [rarely pink], suborbicular, spatulate, oblanceolate, linear-oblanceolate, or, obovate (apex obtuse or emarginate); stamens tetradynamous; filaments not winged, uni- or bilaterally winged, appendaged, or toothed; anthers ovate or oblong; nectar glands (4), 1 on each side of lateral stamen, median glands absent; (placentation apical or parietal). Fruits sessile, ovate-oblong, obovate, or elliptic [obcordate, rarely globose], usually strongly flattened, latiseptate, rarely inflated; valves each not veined (smooth), pubescent or glabrous; replum (visible), rounded; septum complete, (membranous, translucent, veinless); ovules 1 or 2 [or 4-8] per ovary; stigma capitate. Seeds biseriate or aseriate, flattened, winged or not, orbicular or suborbicular to ovoid; seed coat (smooth or minutely reticulate), mucilaginous or not when wetted; cotyledons accumbent or incumbent.
Vascular plants of NE US and adjacent Canada
Pet yellow, varying to white, gradually narrowed to the base; short filaments flanked by a single gland on each side; anthers short and blunt; ovary short, compressed; ovules 1-8 per locule; style slender but short; fr elliptic to orbicular, flattened parallel to the septum, each locule with a few seeds; herbs with entire or serrate lvs; ±pubescent with stellate hairs. 170, mainly Eurasia.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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Species within checklist: Flora of Federal Protected Areas, Desert West
Alyssum alyssoides
Image of Alyssum alyssoides
Alyssum desertorum
Image of Alyssum desertorum
Alyssum minus
Image of Alyssum minus
Alyssum simplex
Image of Alyssum simplex