Athysanus pusillus

(Hooker) Greene

Bull. Calif. Acad. Sci. 1: 72. 1885.

Illustrated
Basionym: Thysanocarpus pusillus Hooker Icon. Pl. 1: plate 42. 1837
Synonyms: Athysanus pusillus var. glabrior S. Watson Thysanocarpus oblongifolius
Treatment appears in FNA Volume 7. Treatment on page 267. Mentioned on page 268.

Plants sparsely to densely pubescent proximally, sometimes glabrous distally. Stems (0.2–) 0.5–3 (–5) dm. Basal leaves: petiole 0.1–0.5 cm; blade oblanceolate, obovate, or oblong, 0.3–1.5 (–2) cm × (1–) 2–6 (–8) mm, margins entire or dentate, apex acute to obtuse, surfaces uniformly pubescent, trichomes cruciform and 3-rayed, adaxially sometimes mixed with coarse, simple ones. Cauline leaves 1–6; blade similar and equaling or smaller than basal. Fruiting pedicels slender, (1.5–) 2–4 (–6) mm. Flowers: sepals 0.5–1 × 0.3–0.7 mm; petals oblong, 1.5–3 × 0.5–1 mm; filaments 0.4–0.6 mm; anthers (0.05–) 0.1–0.2 (–0.25) mm. Fruits usually orbicular to obovate, rarely broadly oblong, 1-locular, not twisted; valves thin, veins sometimes prominent, usually pubescent, rarely glabrous, trichomes simple, to 0.5 mm, hooked (sometimes restricted to margins, or mixed with smaller, sessile, cruciform or 3-rayed ones); septum absent; ovules 2 (–4) per ovary; style 0.05–0.2 mm. Seeds 1, (0.8–) 0.9–1.1 (–1.2) × (0.5–) 0.7–0.9 (–1) mm. 2n = 26.


Phenology: Flowering Feb–Jun.
Habitat: Open grassy slopes, grassy glades in woodlands, chaparral, sandy and gravelly flats, flood plains, rock outcrops, cliffs and ledges, on limestone, serpentine, sandstone, granitic and basaltic substrates
Elevation: 0-1800 m

Distribution

V7 357-distribution-map.gif

B.C., Ariz., Calif., Idaho, Mont., Nev., Oreg., Wash., Mexico (Baja California)

Discussion

Records of Athysanus pusillus for Montana appear to be solely from Ravalli County, and for Nevada from Storey and Washoe counties.

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

... more about "Athysanus pusillus"
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.025 cm0.25 mm <br />2.5e-4 m <br />) +
ovate +  and globose +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
acute +  and obtuse +
Ihsan A. Al-Shehbaz +
(Hooker) Greene +
Thysanocarpus pusillus +
appendaged +  and unappendaged +
1.5 cm15 mm <br />0.015 m <br /> (2 cm20 mm <br />0.02 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
not +  and auriculate +
0.3 cm3 mm <br />0.003 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
dissected +, repand +, sinuate +, crenate +  and dentate +
oblong;obovate;oblong;obovate;oblanceolate +
slender +  and smaller +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
urceolate +, campanulate +  and tubular +
branched +  and simple +
sessile +  and petiolate +
well-developed +
distinct +
indistinct +
not +  and differentiated +
emarginate +  and entire +
B.C. +, Ariz. +, Calif. +, Idaho +, Mont. +, Nev. +, Oreg. +, Wash. +  and Mexico (Baja California) +
0-1800 m +
straight +  and curved +
not winged +  and unappendaged +
connate +  and distinct +
not basally +  and dilated +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
actinomorphic +
indehiscent +  and dehiscent +
oblong +, usually orbicular +  and obovate +
Open grassy slopes, grassy glades in woodlands, chaparral, sandy and gravelly flats, flood plains, rock outcrops, cliffs and ledges, on limestone, serpentine, sandstone, granitic and basaltic substrates +
sessile +  and petiolate +
alternate +, not +  and rosulate +
cauline +  and basal +
connate +  and distinct +
decurrent +
dentate +  and entire +
pinnatifid +
tenuinucellate +, crassinucellate +  and bitegmic +
campylotropous +  and anatropous +
1.5mm;3mm +
rudimentary +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Flowering Feb–Jun. +
trinucleate +  and 3(-11)-colpate +
Bull. Calif. Acad. Sci. +
reflexed +  and recurved +
stout +  and slender +
mucilaginous +
uniseriate +  and biseriate +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
not +  and mucilaginous +
white +, black +, brown +  and yellow +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
oblong +  and flattened +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.09 cm0.9 mm <br />9.0e-4 m <br />) +
persistent +  and caducous +
distinct +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
reduced +
latiseptate +, twisted +  and sessile +
dehiscent +  and indehiscent +
flattened +, oblong +, obovate +  and elliptic +
latiseptate +  and unsegmented +
indehiscent +  and dehiscent +
Illustrated +
tetradynamous +
subequal +
procumbent +  and decumbent +
subsessile +, sessile +  and petiolate +
persistent +
distinct +
0.005 cm0.05 mm <br />5.0e-5 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
Athysanus pusillus var. glabrior +  and Thysanocarpus oblongifolius +
Athysanus pusillus +
Athysanus +
species +
hooked +  and cruciform +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
pubescent +  and glabrous +
anastomosing +
glabrous +  and pubescent +
pubescent +  and glabrous +
rhizomatous +, taprooted +, scapose +  and not +
perennial +, biennial +  and annual +
aquatics +  and terrestrial +
glabrous +  and pubescent +