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maydell's locoweed, maydell's oxytrope

Bessey's locoweed

Habit Plants cespitose, appearing acaulescent. Plants cespitose, appearing acaulescent, herbage silky-pilose.
Leaves

4–14 cm;

stipules stiff, papery, becoming reddish brown, 12–20 mm, free ends caudate-acuminate, pilose to glabrate abaxially, margins ciliate;

leaflets 11–21, blades ovate to lanceolate, elliptic, or oblong, 4–17 × 2–4 mm, apex acute or obtuse, surfaces pilose on midrib abaxially, pilose or glabrous adaxially.

1.5–16 cm;

stipules membranous or papery, light tan or pale gray, silky-pilose;

leaflets 5–25, blades narrowly elliptic, lanceolate, or lanceolate-ovate, 4–21 × 1–4 mm, apex acute or obtuse, surfaces silky-pilose.

Racemes

6–10-flowered, subcapitate, slightly elongate in fruit.

3–22-flowered, subcapitate to loosely racemose in flower, sometimes slightly elongate in fruit.

Peduncles

erect or ascending, 4–15 cm, spreading-villous;

bract lanceolate, shorter to longer than calyx, villous, margins ciliate.

2–19 cm, axis 0.5–8(–10) cm in fruit, hairs appressed or some ascending;

bract ovate-rhombic to lanceolate or lanceolate-acuminate, silky-pilose, margins ciliate.

Corollas

yellowish, keel tip not maculate, 13–17 mm.

bright pink-purple, 17–25 mm, wing petals broadly expanded, often conspicuously 2-lobed apically.

Calyces

short-cylindric, villous, hairs intermixed black and white;

tube 5–6 mm, lobes 1.5–3.2 mm.

cylindric-campanulate, hispid-hirsute, silky-hairy, silky-pilose, or appressed-silky, hairs white;

tube (5–)6–8(–9.5) mm, lobes 2–6 mm.

Legumes

erect, sessile or subsessile, ovoid-ellipsoid, 15–21 × 5–7 mm, length less than or equal to 3 times width, partially bilocular, papery, sulcate adaxially, pilose, hairs black and white.

rupturing calyx but invested by it, erect or spreading, sessile or short-stipitate, stipe to 1.2 mm, cylindric, scarcely to strongly inflated or swollen, (5–)10–14(–20) × 2.5–10 mm, bilocular or semibilocular, papery, villous, hairs whitish, shiny, (1–)1.5–3 mm.

2n

= 96.

Oxytropis maydelliana

Oxytropis besseyi

Phenology Flowering late spring–summer.
Habitat Arctic and alpine tundra, heathlands, alluvial sands, gravels, dry rocky slopes.
Elevation 0–1900 m. (0–6200 ft.)
Distribution
from FNA
AK; BC; NT; NU; QC; YT; e Asia (Chukotsk, Kamchatka)
[BONAP county map]
from USDA
w North America
[WildflowerSearch map]
[BONAP county map]
Discussion

Oxytropis maydelliana has yellowish flowers and reddish brown stipules, which easily characterize this arctic species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Varieties 6 (6 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Legumes sessile; leaflets (5 or)7–25; peduncles surpassed by leaves (or leaves only to proximal­most flowers), axis 2.5–8(–10) cm in fruit; nw Colorado, adjacent Utah, s, c Wyoming.
var. obnapiformis
1. Legumes short-stipitate; leaflets 5–19; peduncles usually surpassing leaves, axis 0.5–5.5 cm (except 2–8 cm in var. besseyi) in fruit; Idaho, Montana, Nevada, Saskatchewan, Utah, Wyoming.
→ 2
2. Calyces silky-hairy or silky-pilose, hairs appressed, sometimes with few ascending hairs.
→ 3
3. Leaflets 5–9; racemes 7–10(–12)-flowered, axes 1–2.5 cm in fruit; Custer County, Idaho.
var. salmonensis
3. Leaflets 7–15; racemes 11–19-flowered, axes 2.5–5.5 cm in fruit; Montana, w Wyoming.
var. fallax
2. Calyces hispid-hirsute, hairs ascending-spreading.
→ 4
4. Racemes loose, axes 2–8 cm in fruit; peduncles 9–19 cm; leaflets 9–19, rachis 2–9 cm, longer than longest leaflet; n Wyoming, Carbon County, Montana, northward to s Saskatchewan.
var. besseyi
4. Racemes subcapitate (at least at anthesis), axes 0.5–2 cm in fruit; peduncles 2–9(–12) cm; leaflets 5–9 (or 11), rachis to 0.5–1.4(–2) cm, usually shorter than lon­gest leaflet; Idaho, Montana, Nevada, Utah, Wyoming.
→ 5
5. Leaflet blades (8–)10–21 mm; Green, Platte, and Wind river drainages, Wyoming and adjacent Montana, Utah.
var. ventosa
5. Leaflet blades 3–10(–13) mm; w Montana and adjacent Idaho, disjunct in Nevada.
var. argophylla
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Oxytropis Fabaceae > subfam. Faboideae > Oxytropis
Sibling taxa
O. arctica, O. besseyi, O. borealis, O. campestris, O. deflexa, O. huddelsonii, O. kobukensis, O. kokrinensis, O. lagopus, O. lambertii, O. mertensiana, O. multiceps, O. nana, O. nigrescens, O. oreophila, O. parryi, O. podocarpa, O. riparia, O. scammaniana, O. sericea, O. splendens
O. arctica, O. borealis, O. campestris, O. deflexa, O. huddelsonii, O. kobukensis, O. kokrinensis, O. lagopus, O. lambertii, O. maydelliana, O. mertensiana, O. multiceps, O. nana, O. nigrescens, O. oreophila, O. parryi, O. podocarpa, O. riparia, O. scammaniana, O. sericea, O. splendens
Subordinate taxa
O. besseyi var. argophylla, O. besseyi var. besseyi, O. besseyi var. fallax, O. besseyi var. obnapiformis, O. besseyi var. salmonensis, O. besseyi var. ventosa
Synonyms O. campestris var. glabrata, O. campestris var. melanocephala, O. maydelliana subsp. melanocephala Aragallus besseyi
Name authority Trautvetter: Fl. Terr. Tschukt., 16. (1878) (Rydberg) Blankinship: Sci. Stud. Montana Coll. Agric., Bot. 1: 80. (1905)
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