Argythamnia humilis

(Engelmann & A. Gray) Müller Arg.

Linnaea 34: 147. 1865.

Common names: Low silverbush
Illustrated
Basionym: Aphora humilis Engelmann & A. Gray Boston J. Nat. Hist. 5: 262. 1845
Synonyms: A. laevis A. Gray ex Torrey A. mercurialina var. pumila Torrey Argythamnia humilis var. laevis (A. Gray ex Torrey) Shinners A. humilis var. leiosperma Waterfall A. laevis (A. Gray ex Torrey) Müller Arg. Ditaxis humilis (Engelmann & A. Gray) Pax D. humilis var. leiosperma (Waterfall) Radcliffe-Smith & Govaerts D. laevis (A. Gray ex Torrey) A. Heller
Treatment appears in FNA Volume 12. Treatment on page 176. Mentioned on page 173, 174.

Herbs, perennial, usually monoecious, rarely dioecious, to 3 dm. Stems erect or prostrate, hairy or glabrous, hairs not silvery, malpighiaceous. Leaves: stipules persistent, ovate to lanceolate, 0.3–1.4 mm, margins not glandular; petiole 2–10 mm; blade obovate to linear, 0.5–7 × 0.2–2.2 cm, margins entire, sometimes slightly revolute, without glands, surfaces hairy or glabrous, hairs not silvery, malpighiaceous. Inflorescences bisexual, rarely unisexual (staminate), 0.7–0.9 cm; bracts ovate to lanceolate, 0.8–2.5 mm, margins without glands. Flowers without pink dye when wetted. Staminate flowers: sepals lanceolate, 2.4–3.3 × 0.3–0.8 mm; petals elliptic, 1.5–2.6 × 0.4–0.8 mm, free from androphore; nectary glands ovate to linear, 0.4–0.8 × 0.2–0.3 mm, adnate to or free from androphore, glabrous, rarely pubescent; stamens (7–) 10, staminodes 2–3, glabrous. Pistillate flowers: sepals elliptic, 4–5.2 × 0.9–2.5 mm, without glands, petals 5, elliptic to filiform, 0.3–1.7 × 0.3–0.4 mm; nectary glands linear to oblong, 0.3–1.5 × 0.1–0.4 mm, glabrous; ovary hispidulous, strigillose, or glabrous; styles 0.6–1.3 mm, glabrous; stigmas flattened. Capsules 1.6–4.2 mm, hispidulous, strigillose, or glabrous. Seeds 1.5–2.5 mm, smooth or rugose-roughened to papillate.


Phenology: Flowering year-round.
Habitat: Pine-oak forests, desert scrub, grasslands, limestone, sandstone, and clay soils.
Elevation: 0–1600 m.

Distribution

V12 112-distribution-map.jpg

Colo., Kans., N.Mex., Okla., Tex., Mexico (Chihuahua), Mexico (Coahuila), Mexico (Nuevo León), Mexico (Tamaulipas)

Discussion

Glabrous plants have been recognized as Argythamnia laevis (and other combinations of Aphora laevis at different taxonomic ranks). B. L. Turner (2001b) studied this variation and concluded that the glabrous plants do not form distinct populations but instead are individuals in otherwise pubescent populations. Argythamnia humilis var. leiosperma was distinguished by possessing smooth seeds, in contrast to the markedly rugose-roughened seeds of var. humilis. When he described the variety, Waterfall mentioned that var. leiosperma is found in populations of western Oklahoma (Cimarron County) and central Texas (Brown and Hamilton counties). However, this taxon has not been recognized in recent treatments of the plants of Texas (G. M. Diggs et al. 1999; Turner et al. 2003) and Oklahoma (R. J. Tyrl et al. 2010) and is not accepted here.

Selected References

None.

Lower Taxa

None.
... more about "Argythamnia humilis"
Yocupitzia Ramírez-Amezcua +
(Engelmann & A. Gray) Müller Arg. +
Aphora humilis +
0.5 cm5 mm <br />0.005 m <br /> (7 cm70 mm <br />0.07 m <br />) +
obovate;linear +
0.2cm;2.2cm +
ovate +  and lanceolate +
glabrous +, strigillose +  and hispidulous +
0.16 cm1.6 mm <br />0.0016 m <br /> (0.42 cm4.2 mm <br />0.0042 m <br />) +
Low silverbush +
Colo. +, Kans. +, N.Mex. +, Okla. +, Tex. +, Mexico (Chihuahua) +, Mexico (Coahuila) +, Mexico (Nuevo León) +  and Mexico (Tamaulipas) +
0–1600 m. +
pistillate +  and staminate +
subtending +
Pine-oak forests, desert scrub, grasslands, limestone, sandstone, and clay soils. +
malpighiaceous +
not silvery +
unisexual +  and bisexual +
0.7 cm7 mm <br />0.007 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
persistent +  and deciduous +
palmate +  and pinnate +
crenate +, repand +  and subentire +
adnate +  and or free +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
glabrous +  and pubescent +
linear +  and oblong +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
extrastaminal +
glabrous;strigillose;glabrous;strigillose;hispidulous +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.17 cm1.7 mm <br />0.0017 m <br />) +
rudimentary +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (1 cm10 mm <br />0.01 m <br />) +
Flowering year-round. +
3(-4)-carpellate +
rugose-roughened +  and papillate +
globose +  and ovoid +
distinct +
4mm (?) +  and 5.2mm (?) +
lanceolate +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Illustrated +
prostrate +  and erect +
flattened +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.14 cm1.4 mm <br />0.0014 m <br />) +
connate +  and distinct +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (?) +  and 0.13 cm1.3 mm <br />0.0013 m <br /> (?) +
glabrous +  and hairy +
A. laevis +, A. mercurialina var. pumila +, Argythamnia humilis var. laevis +, A. humilis var. leiosperma +, Ditaxis humilis +, D. humilis var. leiosperma +  and D. laevis +
Argythamnia humilis +
Argythamnia +
species +
dioecious +  and monoecious +