Alyssum alyssoides

(Linnaeus) Linnaeus

Syst. Nat. ed. 10, 2: 1130. 1759.

WeedyIntroduced
Basionym: Clypeola alyssoides Linnaeus Sp. Pl. 2: 652. 1753
Synonyms: Alyssum calycinum Linnaeus
Treatment appears in FNA Volume 7. Treatment on page 248.

Annuals; canescent throughout, trichomes appressed, 6–10-rayed, mixed with simple and forked on pedicels and sepals. Stems simple or few to several from base, erect, ascending, or decumbent, (unbranched or branched distally), 0.5–3.5 (–5) dm. Cauline leaves subsessile or (proximal) shortly petiolate; blade usually narrowly oblanceolate to linear, sometimes spatulate or obovate, 3–4 (–4.5) cm × (0.5–) 1–3.5 (–5) mm, base attenuate or cuneate, apex obtuse or acute. Fruiting pedicels divaricate or ascending, straight, slender, 2–5 (–6) mm, trichomes stellate, with fewer, simple and forked ones. Flowers: sepals (persistent) oblong, (1.5–) 2–3 × 0.7–1.1 mm, pubescent as pedicels; petals (often persistent) white or pale-yellow, usually linear to linear-oblanceolate, rarely obovate, 2–3 (–4) × 0.3–0.7 (–1) mm, apex emarginate, glabrous or sparsely stellate-pubescent abaxially; filaments (slender) not appendaged, toothed, or winged, 1–1.5 mm; anthers ovate, 0.15–0.2 mm. Fruits orbicular, (2–) 3–4 (–5) mm diam., apex emarginate or truncate; valves uniformly inflated at middle, strongly flattened at margins, sparsely stellate-pubescent; ovules 2 per ovary; style (slender), 0.3–0.6 (–1) mm, basally stellate-pubescent or glabrous. Seeds oblong to ovoid, compressed, 1.1–2 × 0.7–1.1 mm, margins narrow, ca. 0.1 mm wide. 2n = 32.


Phenology: Flowering May–Jul.
Habitat: Roadsides, railways, waste grounds, disturbed sites, grassy areas, fields, sagebrush flats, limestone ledges or bluffs
Elevation: 0-1800 m

Distribution

V7 319-distribution-map.gif

Introduced; Alta., B.C., Man., Nfld. and Labr. (Nfld.), Ont., Que., Sask., Alaska, Ariz., Calif., Colo., Conn., Idaho, Ill., Ind., Iowa, Kans., Maine, Md., Mass., Mich., Mont., N.J., N.Mex., N.Y., Ohio, Oreg., Pa., R.I., S.Dak., Utah, Vt., Va., Wash., W.Va., Wis., Wyo., Europe, sw Asia, n Africa

Discussion

Selected References

None.

Lower Taxa

None.

"elongated" is not a number."thick" is not a number."dm" is not declared as a valid unit of measurement for this property.

... more about "Alyssum alyssoides"
0.015 cm0.15 mm <br />1.5e-4 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
truncate +  and emarginate +
stellate-pubescent +  and glabrous +
Acute (?) +  and Obtuse (?) +
Ihsan A. Al-Shehbaz +
(Linnaeus) Linnaeus +
sessile +  and petiolate +
not +  and rosulate +
cuneate +  and attenuate +
Clypeola alyssoides +
appendaged +  and unappendaged +
4 cm40 mm <br />0.04 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
3 cm30 mm <br />0.03 m <br /> (4 cm40 mm <br />0.04 m <br />) +
dissected +, repand +, sinuate +, crenate +  and dentate +
obovate;spatulate;usually narrowly oblanceolate;linear +
much smaller +  and reduced +
1mm;3.5mm +
urceolate +, campanulate +  and tubular +
branched +  and simple +
petiolate +  and subsessile +
well-developed +
distinct +
not +  and differentiated +
emarginate +  and entire +
incumbent +  and accumbent +
Alta. +, B.C. +, Man. +, Nfld. and Labr. (Nfld.) +, Ont. +, Que. +, Sask. +, Alaska +, Ariz. +, Calif. +, Colo. +, Conn. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, Maine +, Md. +, Mass. +, Mich. +, Mont. +, N.J. +, N.Mex. +, N.Y. +, Ohio +, Oreg. +, Pa. +, R.I. +, S.Dak. +, Utah +, Vt. +, Va. +, Wash. +, W.Va. +, Wis. +, Wyo. +, Europe +, sw Asia +  and n Africa +
0-1800 m +
straight +  and curved +
winged +  and not appendaged +
connate +  and distinct +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
actinomorphic +
latiseptate +  and sessile +
orbicular +
latiseptate +  and unsegmented +
Roadsides, railways, waste grounds, disturbed sites, grassy areas, fields, sagebrush flats, limestone ledges or bluffs +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
pinnatifid +
forked +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
rudimentary +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
Flowering May–Jul. +
trinucleate +  and 3(-11)-colpate +
Syst. Nat. ed. +
elongated +
reflexed +  and ascending +
stout +  and slender +
not +  and branched +
not +  and mucilaginous +
not +  and winged +
aseriate +  and biseriate +
not +  and mucilaginous +
White (?) +, Black (?) +, Brown (?) +  and Yellow (?) +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
compressed +, oblong +  and ovoid +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
persistent +  and caducous +
distinct +
erect +  and spreading +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
reduced +
latiseptate +, schizocarpic +, samaroid +  and lomentaceous +
indehiscent +  and dehiscent +
angustiseptate +, flat +, angled +, terete +, torulose +, not +, segmented +  and nutletlike +
Weedy +  and Introduced +
tetradynamous +
few to several +  and simple +
procumbent +  and decumbent +
decumbent +, ascending +  and erect +
subsessile +, sessile +  and petiolate +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
persistent +
distinct +
glabrous +  and stellate-pubescent +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
Alyssum calycinum +
Alyssum alyssoides +
species +
simple +  and sessile +
stellate-pubescent +
flattened +  and inflated +
anastomosing +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
subshrub +  and herb +
aquatics +  and terrestrial +
glabrous +  and pubescent +