1. Alyssum Linnaeus, Sp. Pl. 2: 650. 1753; Gen. Pl. ed. 5, 293. 1754.
Madwort [Greek, a-, not or without, and lyssa, rabies or madness; name used for plants reputed in ancient times as remedy for hydrophobia, cure for madness, and calmative for anger] Madwort [Greek, a-, not or without, and lyssa, rabies or madness; name used for plants reputed in ancient times as remedy for hydrophobia, cure for madness, and calmative for anger]
Ihsan A. Al-Shehbaz
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.
Species ca. 170 (6 in the flora): North America, se Europe, Asia, n Africa.
SELECTED REFERENCES Dudley, T. R. 1964. Studies in Alyssum: Near Eastern representatives and their allies, I. J. Arnold Arbor. 45: 57-100. Dudley, T. R. 1964b. Synopsis of the genus Alyssum. J. Arnold Arbor. 45: 358-373. Dudley, T. R. 1965. Studies in Alyssum: Near Eastern representatives and their allies, II. Section Meniocus and section Psilonema. J. Arnold Arbor. 46: 181-217. Dudley, T. R. 1966. Ornamental madworts (Alyssum) and the correct name of the goldentuft alyssum. Arnoldia (Jamaica Plain) 26: 33-48. Dudley, T. R. 1968. Alyssum (Cruciferae) introduced in North America. Rhodora 70: 298-300.