Atriplex powellii var. minuticarpa

(Stutz & G. L. Chu) S. L. Welsh

Rhodora 102: 421. 2001.

Common names: Smallbract orach
Endemic
Basionym: Atriplex minuticarpa Stutz & G. L. Chu Madroño 40: 161, fig. 1. 1993
Treatment appears in FNA Volume 4. Treatment on page 353. Mentioned on page 352.

Herbs, monoecious, (0.5–) 1–4.5 dm. Leaves on petioles 0.3–1.5 (–2) cm proximally, becoming sessile distally, blade inconspicuously 3-veined, deltoid-ovate to orbicular-ovate or cordate-ovate, 5–20 (–30) mm and as wide, base broadly cuneate to subcordate, apex acute to shortly acuminate, scurfy. Flowers of both sexes intermixed in axillary glomerules. Staminate flowers 5-merous. Fruiting bracteoles ovate-oblong or oval to obovate, 1.5–2.5 × 1–2.5 mm, subentire to tridentate apically, median tooth largest, lateral lobes often rounded and sometimes constricted basally, giving an overall violin shape, sometimes slenderly appendaged marginally and bicristate on at least 1 face, but typically unappendaged on faces. Seeds yellowbrown, 0.9–1.2 mm.


Phenology: Flowering spring–fall.
Habitat: Tununk and Blue Gate members Mancos Shale Formation and on Morrison Formation, and likely on other fine-textured saline substrates, with mat-atriplex, greasewood, rabbitbrush, and shadscale communities
Elevation: 1200-1400 m

Discussion

This entity is completely within the distribution of var. powellii in southeast Utah, where it occurs on the fine-textured saline and seleniferous silts and clays of exposed Jurassic and Cretaceous strata. The habits of growth of the two taxa are essentially identical, and the shape of both the foliage and bracteate leaves is essentially the same. The fruiting bracteoles of var. minuticarpa, though small, occasionally bear finger-like surficial appendages and share the rounded lateral lobes marginal to the terminal cusp and violin shape with var. powellii. This small-bracteolate plant evidently occupies a much more limited set of ecological circumstances than its near ally.

Selected References

None.

Lower Taxa

None.

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

Stanley L. Welsh +
(Stutz & G. L. Chu) S. L. Welsh +
slippery +
aromatic +
broadly cuneate +  and subcordate +
Atriplex minuticarpa +
2 cm20 mm <br />0.02 m <br /> (3 cm30 mm <br />0.03 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (5 cm50 mm <br />0.05 m <br />) +
deltoid-ovate +  and orbicular-ovate or cordate-ovate +
0.5 cm5 mm <br />0.005 m <br /> (2 cm20 mm <br />0.02 m <br />) +
0.2cm;3cm +
persistent +  and deciduous +
reddish-brown +, black +, brown +  and green +
0 +  and 1/2 +
cuneate +  and ovate or obovate +
4-5-lobed +
Smallbract orach +
1200-1400 m +
smooth +  and tuberculate +
5-merous +  and staminate +
rarely +  and lacking +
unisexual +  and bisexual +
not +  and connate +
enlarged +
Tununk and Blue Gate members Mancos Shale Formation and on Morrison Formation, and likely on other fine-textured saline substrates, with mat-atriplex, greasewood, rabbitbrush, and shadscale communities +
arachnoid +  and scurfy +
bladderlike +
terminal +  and axillary +
unappendaged +  and appendaged +
constricted +
deciduous +  and persistent +
not winged +  and winged +
lobed +  and serrate-dentate +
stipitate +, sessile +  and monomorphic +
inferior +, half-inferior +  and superior +
crassinucellate +  and bitegmic +
campylotropous +
1 +  and single +
persistent +  and deciduous +
(1-)3-5-lobed +
papery +  and chartaceous +
1.5 cm15 mm <br />0.015 m <br /> (2 cm20 mm <br />0.02 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
Flowering spring–fall. +
tridentate +  and cuspidate +
petiolate +, short +  and subsessile +
bulbous +  and taprooted +
fusiform +
fleshy +  and fibrous +
verrucate +  and striate +
flattened +
cylindric +
3 (?) +  and 5 (?) +
opposite +  and alternate +
slender +  and stout +
succulent +
sessile +  and petiolate +
reduced;small +
horizontal +  and vertical +
verrucate +
tridentate +  and cuspidate +
Obione powellii +
Atriplex powellii var. minuticarpa +
Atriplex powellii +
variety +
dicotyledonous +
subentire;tridentate +