Alyssum

Linnaeus

Sp. Pl. 2: 650. 1753.

,

Gen. Pl. ed. 5, 293. 1754.

Common names: Madwort
Etymology: 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
Treatment appears in FNA Volume 7. Treatment on page 247. Mentioned on page 226, 237, 241.
 TaxonIllustrator 
FNA7 P32 Alyssum simplex.jpegAlyssum simplex
Aurinia saxatilis
Berteroa incana
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey

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.

Distribution

North America, se Europe, Asia, n Africa

Discussion

Species ca. 170 (6 in the flora).

Alyssum has five introduced and one native species in North America. It is taxonomically difficult and is centered in Turkey and adjacent countries. For the determination of most species, both flowers and mature fruits are needed. Alyssum has been split into nine or more segregates; the segregates are based on the presence of staminal appendages, petal color, and number of ovules per ovary. In the absence of thorough molecular studies on Alyssum and its immediate relatives, it is more practical to delimit the genus broadly, as done here.

Key

1 Perennials; ovules 1 or 2 per ovary > 2
1 Annuals; ovules 2 per ovary > 3
2 Cauline leaf blades broadly oblanceolate, obovate-spatulate, or obovate; stems 0.7-1.5(-2) dm; ovules (1 or) 2 per ovary; seeds not winged or margined, 1-1.7 mm. Alyssum obovatum
2 Cauline leaf blades narrowly oblanceolate to linear; stems (2.5-)3-6(-7) dm; ovules 1 per ovary; seeds broadly winged, 3-3.8 mm. Alyssum murale
3 Fruits usually glabrous, rarely sparsely pubescent (when young). Alyssum desertorum
3 Fruits pubescent throughout > 4
4 Sepals persistent; filaments not appendaged, toothed, or winged (slender). Alyssum alyssoides
4 Sepals caducous; filaments at least some appendaged, toothed, or winged (expanded basally) > 5
5 Fruits orbicular; fruiting pedicels divaricate. Alyssum simplex
5 Fruits ovate-oblong; fruiting pedicels ascending to suberect. Alyssum szowitsianum

"elongated" is not a number."thick" is not a number.

... more about "Alyssum"
oblong +  and ovate +
Ihsan A. Al-Shehbaz +
Linnaeus +
sessile +  and petiolate +
not +  and rosulate +
appendaged +  and unappendaged +
dissected +, repand +, sinuate +, crenate +  and dentate +
much smaller +  and reduced +
urceolate +, campanulate +  and tubular +
branched +  and simple +
sessile +  and petiolate +
well-developed +
distinct +
not +  and differentiated +
Madwort +
emarginate +  and entire +
incumbent +  and accumbent +
North America +, se Europe +, Asia +  and n Africa +
straight +  and curved +
Greek, a-, not or without, and lyssa, rabies or madness +  and name used for plants reputed in ancient times as remedy for hydrophobia, cure for madness, and calmative for anger +
appendaged +, winged +  and not winged +
connate +  and distinct +
actinomorphic +
latiseptate +  and sessile +
inflated +, flattened +, elliptic +, obovate +  and ovate-oblong +
latiseptate +  and unsegmented +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
pinnatifid +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
rudimentary +
trinucleate +  and 3(-11)-colpate +
Sp. Pl. +  and Gen. Pl. ed. +
1753 +  and 1754 +
elongated +
reflexed +  and ascending +
stout +  and slender +
not +  and branched +
dudley1964a +, dudley1964b +, dudley1965a +, dudley1966a +  and dudley1968a +
not +  and mucilaginous +
not +  and winged +
aseriate +  and biseriate +
not +  and mucilaginous +
White (?) +, Black (?) +, Brown (?) +  and Yellow (?) +
suborbicular +  and ovoid +
persistent +  and caducous +
distinct +
erect +  and spreading +
oblong +  and ovate +
reduced +
latiseptate +, schizocarpic +, samaroid +  and lomentaceous +
indehiscent +  and dehiscent +
angustiseptate +, flat +, angled +, terete +, torulose +, not +, segmented +  and nutletlike +
tetradynamous +
branched +  and unbranched +
procumbent +  and decumbent +
decumbent +, ascending +  and erect +
subsessile +, sessile +  and petiolate +
persistent +
distinct +
Cruciferae +
Alyssum +
Brassicaceae tribe Alysseae +
simple +  and sessile +
glabrous +  and pubescent +
anastomosing +
perennial +  and annual +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +