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arcane milkvetch, basalt milk vetch

timber milk-vetch, weedy milk-vetch

Habit Plants slender, delicate, wiry, caulescent, 15–40 cm, strigulose, hairs basifixed; from superficial to slightly subterranean branched caudex. Plants clump-forming, caulescent or shortly caulescent, 1–35 cm, strigose, strigulose-pilosulous, pilosulous, strigulose, or villous, hairs basifixed or malpighian; from ± superficial, branched caudex.
Stems

decumbent to ascending, strigulose.

decumbent to erect, sterile branches forming tuft of sub-basal leaves, strigose, strigulose, or villous.

Leaves

(2.5–)4–10 cm;

stipules 1.5–2.5 mm, papery at proximal nodes, herbaceous or with herbaceous tips at distal nodes;

leaflets (5 or)7–13, blades broadly oblong-elliptic to lanceolate-oblong or linear-elliptic, 2–10(–15) mm, apex obtuse to truncate, shallowly retuse, or subacute, surfaces strigulose abaxially, sparsely strigulose or glabrous adaxially.

1.5–20 cm;

stipules connate-sheathing (bidentate) at proximal nodes, shortly connate or distinct at distal nodes, 1.5–9 mm, papery-membranous throughout or, sometimes, herbaceous at distal nodes;

leaflets 3–21, blades linear, oblong, elliptic, linear-elliptic, linear-oblanceolate, lanceolate, oblong-elliptic, elliptic-lanceolate, or, rarely, filiform-subulate (distally), 2–30(–42) × 0.5–7 mm, apex acute, obtuse, acuminate, apiculate, or, rarely, retuse, surfaces strigose, glabrescent, or glabrous abaxially, glabrous, glabrescent, or sparsely hairy adaxially;

terminal leaflet sometimes decurrent distally, not jointed to rachis.

Racemes

(3–)6–14-flowered, flowers ascending;

axis (1–)2–8 cm in fruit;

bracts 0.8–2.5 mm;

bracteoles 0–2.

3–19(–24)-flowered, flowers spreading-declined;

axis 1–14 cm in fruit;

bracts 0.6–4 mm;

bracteoles usually 0.

Peduncles

straight, sometimes incurved-ascending, 3–15 cm.

usually incurved-ascending, 2–14 cm.

Pedicels

0.5–2.2 mm.

0.8–3 mm.

Flowers

7–10.5 mm;

calyx short-cylindric, (3.1–)3.6–5.5 mm, strigulose, tube (2.3–)2.8–4 mm, lobes triangular to subulate, 0.4–1.6 mm;

corolla ochroleucous or whitish suffused with lilac;

banner recurved through 45°;

keel (6.3–)7–10 mm, apex triangular and beaklike.

5.3–10.6 mm;

calyx (2.3–)2.4–6 mm, strigose, tube 1.7–4.2 mm, lobes subulate, 0.5–2.6 mm;

corolla lilac, pink-purple, ochroleucous, or whitish, often suffused, lined, or veined with purple;

banner recurved through 40–90°;

keel 5.9–10.7(–11.4) mm, apex beaklike.

Legumes

persistent on receptacle until well after maturity, falling while still attached to pedicel, erect, stramineous, straight, linear-oblong, obtusely 3-sided compressed, 10–25 × 2.4–3.3 mm, ± bilocular, thinly fleshy becoming leathery, strigulose;

septum 1–1.4 mm wide;

sessile or subsessile.

declined-pendulous; green, sometimes with purple speckles, becoming brown or stramineous, straight or nearly so, linear, linear-oblong, linear-ellipsoid, or oblanceoloid, laterally compressed, bicarinate by sutures, 11–25 × (1.2–)2–4 mm, papery, usually strigulose, villosulous, or glabrous, rarely with few hairs;

stipe 0–1 mm.

Seeds

14–23.

6–19.

Astragalus obscurus

Astragalus miser

Phenology Flowering May–Jul.
Habitat Sandy to fine-textured substrates or gravelly slopes, with juniper, sagebrush, bitterbrush, or rabbitbrush.
Elevation 900–2300 m. (3000–7500 ft.)
Distribution
from FNA
CA; ID; NV; OR
[WildflowerSearch map]
[BONAP county map]
from USDA
w North America
[WildflowerSearch map]
[BONAP county map]
Discussion

Astragalus obscurus occurs in northern and north-central California, southwestern Idaho, northern and western Nevada, and southeastern Oregon.

R. C. Barneby (1964) discussed variation in Astragalus obscurus, including one morphologically differentiated outlier from the northern foothills of Mount Shasta in Siskiyou County, which may represent a distinct variety.

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

Varieties 8 (8 in the flora).

Astragalus miser, widespread in the American West, contains miserotoxin, a nitrogenous compound that is poisonous to cattle and sheep. In the key to varieties the presence of malpighian hairs is important. The point of attachment may be so near the base as to be almost indistinguishable from a basifixed trichome. The key is tentative and will not always reliably separate varieties; nevertheless, morphological trends exist and most plants are identifiable.

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

Key
1. Herbage hairs obscurely malpighian; leaflet blades pubescent.
→ 2
2. Herbage villosulous or villous and pilosulous, hairs gray or silvery, mostly twisted and loose; legumes minutely villosulous, hairs twisted; ec Idaho, adjoining Montana.
var. crispatus
2. Herbage strigulose, hairs ± straight; legumes strigulose; Idaho, Montana, Wyoming.
→ 3
3. Leaflet blades linear to linear-elliptic or oblong-elliptic; corollas whitish, ochro­leu­cous, or stramineous, sometimes brownish-veined, keel apex maculate; seeds 7–11; sw Montana, ec Idaho, nw Wyoming.
var. praeteritus
3. Leaflet blades narrowly elliptic to elliptic-lanceolate (leaves subtending racemes sometimes broadly elliptic or oblanceolate); corollas usually pink-purple, purplish, bluish, or dull purple, sometimes pallid or whitish, except maculate keel; seeds 12–18; Idaho and s Montana to c Wyoming.
var. decumbens
1. Herbage hairs basifixed; leaflet blades abaxially pubescent, adaxially pubescent or glabrous.
→ 4
4. Leaflet blades with pubescent surfaces, hairs silvery or cinereous; calyces (4.2–)4.6–6 mm; corollas lilac or pink-purple, banners (9.5–)9.8–12 mm, keel (7.8–)8.6–10.7 mm; legumes densely strigulose; ne Washington to w Montana and adjacent Canada.
var. miser
4. Leaflet blades with surfaces pubescent or glabrous abaxially, usually glabrous or gla­brate adaxially, sometimes pubescent; calyces 2.4–5.6 mm; corollas usually whitish, rarely ochroleucous, sometimes suffused or lined or veined with purple, banners (5.2–)6–13 mm, keel 5.9–10 mm; legumes strigulose or gla­brous; British Columbia and Alberta south­ward to Washington, Arizona, New Mexico, and South Dakota.
→ 5
5. Leaflets (3–)7–11; stems 1–11(–15) cm; banners 6–8 mm; legumes linear (in profile), strigulose; seeds 8–12; se Idaho to sw Montana, ne Nevada, n Utah, and w Wyoming.
var. tenuifolius
5. Leaflets (9 or)11–21; stems 1–35 cm; banners (5.2–)6.5–13 mm; legumes oblanceolate, linear, linear-oblong, -elliptic, or -oblanceolate (in pro­file), glabrous or strigulose; seeds (6 or)7–19; British Columbia and Alberta southward to Washington, Arizona, New Mexico, and South Dakota.
→ 6
6. Legumes strigulose; seeds 13–19; Montana to New Mexico, west to Nevada and Arizona.
var. oblongifolius
6. Legumes glabrous, strigulose, or few hairs present; seeds (6 or)7–11; South Dakota west to British Columbia and Washington.
→ 7
7. Stems 10–35 cm; banners 7–9.5 mm, keel 6–7.8(–8.4) mm; leaflet blades narrowly elliptic to linear or linear-oblanceolate; legumes glabrous or strigulose; Alberta and British Columbia southward to Montana, Idaho, and Washington.
var. serotinus
7. Stems 1–15 cm; banners (5.2–)6.5–13 mm, keel (7.1–)8–10(–11.4) mm; leaflet blades narrowly to broadly elliptic, lanceolate, or lanceolate-oblong; legumes usually glabrous, rarely with few, scattered hairs; w Wyoming and Montana, adjoining Idaho, and Black Hills of South Dakota.
var. hylophilus
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Astragalus > sect. Reventi-arrecti Fabaceae > subfam. Faboideae > Astragalus > sect. Genistoidei
Sibling taxa
A. accidens, A. accumbens, A. ackermanii, A. acutirostris, A. adanus, A. aequalis, A. agnicidus, A. agrestis, A. albens, A. albulus, A. allochrous, A. alpinus, A. altus, A. alvordensis, A. amblytropis, A. americanus, A. amnis-amissi, A. amphioxys, A. ampullarioides, A. ampullarius, A. andersonii, A. anisus, A. anserinus, A. applegatei, A. aquilonius, A. aretioides, A. argophyllus, A. aridus, A. arizonicus, A. arrectus, A. arthurii, A. asclepiadoides, A. asotinensis, A. asymmetricus, A. atratus, A. atropubescens, A. atwoodii, A. austiniae, A. australis, A. barnebyi, A. barrii, A. beathii, A. beatleyae, A. beckwithii, A. bernardinus, A. bibullatus, A. bicristatus, A. bisulcatus, A. bodinii, A. bolanderi, A. bourgovii, A. brandegeei, A. brauntonii, A. brazoensis, A. breweri, A. californicus, A. callithrix, A. calycosus, A. camptopus, A. canadensis, A. caricinus, A. casei, A. castaneiformis, A. castetteri, A. ceramicus, A. cerussatus, A. chamaeleuce, A. chamaemeniscus, A. chinensis, A. chloödes, A. chuskanus, A. cibarius, A. cicer, A. cimae, A. claranus, A. clevelandii, A. cliffordii, A. cobrensis, A. coccineus, A. collinus, A. coltonii, A. columbianus, A. concordius, A. congdonii, A. conjunctus, A. consobrinus, A. contortuplicatus, A. convallarius, A. cottamii, A. crassicarpus, A. cremnophylax, A. cronquistii, A. crotalariae, A. curtipes, A. curvicarpus, A. cusickii, A. cutleri, A. cyaneus, A. cymboides, A. deanei, A. debequaeus, A. desereticus, A. desperatus, A. deterior, A. detritalis, A. diaphanus, A. didymocarpus, A. distortus, A. diversifolius, A. douglasii, A. drabelliformis, A. drummondii, A. duchesnensis, A. eastwoodiae, A. egglestonii, A. emoryanus, A. endopterus, A. ensiformis, A. episcopus, A. equisolensis, A. eremiticus, A. ertterae, A. eucosmus, A. eurekensis, A. eurylobus, A. falcatus, A. feensis, A. filipes, A. flavus, A. flexuosus, A. fucatus, A. funereus, A. gambelianus, A. geyeri, A. gibbsii, A. giganteus, A. gilensis, A. gilmanii, A. gilviflorus, A. glycyphyllos, A. gracilis, A. grayi, A. gypsodes, A. hallii, A. hamiltonii, A. harrisonii, A. heilii, A. henrimontanensis, A. holmgreniorum, A. hoodianus, A. hornii, A. howellii, A. humillimus, A. humistratus, A. hyalinus, A. hypoxylus, A. inflexus, A. insularis, A. inversus, A. inyoensis, A. iodanthus, A. iodopetalus, A. iselyi, A. jaegerianus, A. jejunus, A. johannis-howellii, A. kelseyae, A. kentrophyta, A. kerrii, A. knightii, A. laccoliticus, A. lancearius, A. laxmannii, A. layneae, A. leibergii, A. lemmonii, A. lentiformis, A. lentiginosus, A. leptaleus, A. leptocarpus, A. leucolobus, A. limnocharis, A. lindheimeri, A. linifolius, A. loanus, A. lonchocarpus, A. lotiflorus, A. lutosus, A. lyallii, A. macrodon, A. magdalenae, A. malacoides, A. malacus, A. megacarpus, A. michauxii, A. microcymbus, A. microcystis, A. microlobium, A. micromerius, A. miguelensis, A. minthorniae, A. misellus, A. miser, A. missouriensis, A. moencoppensis, A. mohavensis, A. mollissimus, A. molybdenus, A. monoensis, A. montii, A. monumentalis, A. mulfordiae, A. multiflorus, A. musiniensis, A. naturitensis, A. neglectus, A. nelsonianus, A. neomexicanus, A. nevinii, A. newberryi, A. nidularius, A. nothoxys, A. nudisiliquus, A. nutans, A. nutriosensis, A. nuttallianus, A. nuttallii, A. nutzotinensis, A. nyensis, A. obcordatus, A. oniciformis, A. oocalycis, A. oocarpus, A. oophorus, A. oreganus, A. osterhoutii, A. oxyphysus, A. pachypus, A. palmeri, A. panamintensis, A. pardalinus, A. parryi, A. pattersonii, A. pauperculus, A. paysonii, A. peckii, A. pectinatus, A. perianus, A. phoenix, A. pictiformis, A. pinonis, A. piscator, A. piutensis, A. plattensis, A. platytropis, A. polaris, A. pomonensis, A. porrectus, A. praelongus, A. preussii, A. proimanthus, A. proximus, A. pseudiodanthus, A. pterocarpus, A. pubentissimus, A. pulsiferae, A. puniceus, A. purshii, A. pycnostachyus, A. racemosus, A. rafaelensis, A. rattanii, A. ravenii, A. recurvus, A. reflexus, A. remotus, A. reventiformis, A. reventus, A. riparius, A. ripleyi, A. robbinsii, A. rusbyi, A. sabulonum, A. sabulosus, A. salmonis, A. saurinus, A. scaphoides, A. schmolliae, A. sclerocarpus, A. scopulorum, A. sepultipes, A. serenoi, A. sericoleucus, A. serpens, A. sesquiflorus, A. sheldonii, A. shevockii, A. shortianus, A. siliceus, A. simplicifolius, A. sinuatus, A. solitarius, A. sophoroides, A. soxmaniorum, A. spaldingii, A. sparsiflorus, A. spatulatus, A. speirocarpus, A. straturensis, A. striatiflorus, A. subcinereus, A. subvestitus, A. succumbens, A. tegetarioides, A. tener, A. tennesseensis, A. tephrodes, A. terminalis, A. tetrapterus, A. thurberi, A. tibetanus, A. tidestromii, A. tiehmii, A. titanophilus, A. toanus, A. toquimanus, A. tortipes, A. traskiae, A. tricarinatus, A. trichopodus, A. tridactylicus, A. troglodytus, A. tweedyi, A. tyghensis, A. umbellatus, A. umbraticus, A. uncialis, A. utahensis, A. vaccarum, A. vallaris, A. vexilliflexus, A. villosus, A. wardii, A. waterfallii, A. webberi, A. welshii, A. wetherillii, A. whitneyi, A. williamsii, A. wingatanus, A. wittmannii, A. woodruffii, A. wootonii, A. wrightii, A. xiphoides, A. yoderwilliamsii, A. zionis
A. accidens, A. accumbens, A. ackermanii, A. acutirostris, A. adanus, A. aequalis, A. agnicidus, A. agrestis, A. albens, A. albulus, A. allochrous, A. alpinus, A. altus, A. alvordensis, A. amblytropis, A. americanus, A. amnis-amissi, A. amphioxys, A. ampullarioides, A. ampullarius, A. andersonii, A. anisus, A. anserinus, A. applegatei, A. aquilonius, A. aretioides, A. argophyllus, A. aridus, A. arizonicus, A. arrectus, A. arthurii, A. asclepiadoides, A. asotinensis, A. asymmetricus, A. atratus, A. atropubescens, A. atwoodii, A. austiniae, A. australis, A. barnebyi, A. barrii, A. beathii, A. beatleyae, A. beckwithii, A. bernardinus, A. bibullatus, A. bicristatus, A. bisulcatus, A. bodinii, A. bolanderi, A. bourgovii, A. brandegeei, A. brauntonii, A. brazoensis, A. breweri, A. californicus, A. callithrix, A. calycosus, A. camptopus, A. canadensis, A. caricinus, A. casei, A. castaneiformis, A. castetteri, A. ceramicus, A. cerussatus, A. chamaeleuce, A. chamaemeniscus, A. chinensis, A. chloödes, A. chuskanus, A. cibarius, A. cicer, A. cimae, A. claranus, A. clevelandii, A. cliffordii, A. cobrensis, A. coccineus, A. collinus, A. coltonii, A. columbianus, A. concordius, A. congdonii, A. conjunctus, A. consobrinus, A. contortuplicatus, A. convallarius, A. cottamii, A. crassicarpus, A. cremnophylax, A. cronquistii, A. crotalariae, A. curtipes, A. curvicarpus, A. cusickii, A. cutleri, A. cyaneus, A. cymboides, A. deanei, A. debequaeus, A. desereticus, A. desperatus, A. deterior, A. detritalis, A. diaphanus, A. didymocarpus, A. distortus, A. diversifolius, A. douglasii, A. drabelliformis, A. drummondii, A. duchesnensis, A. eastwoodiae, A. egglestonii, A. emoryanus, A. endopterus, A. ensiformis, A. episcopus, A. equisolensis, A. eremiticus, A. ertterae, A. eucosmus, A. eurekensis, A. eurylobus, A. falcatus, A. feensis, A. filipes, A. flavus, A. flexuosus, A. fucatus, A. funereus, A. gambelianus, A. geyeri, A. gibbsii, A. giganteus, A. gilensis, A. gilmanii, A. gilviflorus, A. glycyphyllos, A. gracilis, A. grayi, A. gypsodes, A. hallii, A. hamiltonii, A. harrisonii, A. heilii, A. henrimontanensis, A. holmgreniorum, A. hoodianus, A. hornii, A. howellii, A. humillimus, A. humistratus, A. hyalinus, A. hypoxylus, A. inflexus, A. insularis, A. inversus, A. inyoensis, A. iodanthus, A. iodopetalus, A. iselyi, A. jaegerianus, A. jejunus, A. johannis-howellii, A. kelseyae, A. kentrophyta, A. kerrii, A. knightii, A. laccoliticus, A. lancearius, A. laxmannii, A. layneae, A. leibergii, A. lemmonii, A. lentiformis, A. lentiginosus, A. leptaleus, A. leptocarpus, A. leucolobus, A. limnocharis, A. lindheimeri, A. linifolius, A. loanus, A. lonchocarpus, A. lotiflorus, A. lutosus, A. lyallii, A. macrodon, A. magdalenae, A. malacoides, A. malacus, A. megacarpus, A. michauxii, A. microcymbus, A. microcystis, A. microlobium, A. micromerius, A. miguelensis, A. minthorniae, A. misellus, A. missouriensis, A. moencoppensis, A. mohavensis, A. mollissimus, A. molybdenus, A. monoensis, A. montii, A. monumentalis, A. mulfordiae, A. multiflorus, A. musiniensis, A. naturitensis, A. neglectus, A. nelsonianus, A. neomexicanus, A. nevinii, A. newberryi, A. nidularius, A. nothoxys, A. nudisiliquus, A. nutans, A. nutriosensis, A. nuttallianus, A. nuttallii, A. nutzotinensis, A. nyensis, A. obcordatus, A. obscurus, A. oniciformis, A. oocalycis, A. oocarpus, A. oophorus, A. oreganus, A. osterhoutii, A. oxyphysus, A. pachypus, A. palmeri, A. panamintensis, A. pardalinus, A. parryi, A. pattersonii, A. pauperculus, A. paysonii, A. peckii, A. pectinatus, A. perianus, A. phoenix, A. pictiformis, A. pinonis, A. piscator, A. piutensis, A. plattensis, A. platytropis, A. polaris, A. pomonensis, A. porrectus, A. praelongus, A. preussii, A. proimanthus, A. proximus, A. pseudiodanthus, A. pterocarpus, A. pubentissimus, A. pulsiferae, A. puniceus, A. purshii, A. pycnostachyus, A. racemosus, A. rafaelensis, A. rattanii, A. ravenii, A. recurvus, A. reflexus, A. remotus, A. reventiformis, A. reventus, A. riparius, A. ripleyi, A. robbinsii, A. rusbyi, A. sabulonum, A. sabulosus, A. salmonis, A. saurinus, A. scaphoides, A. schmolliae, A. sclerocarpus, A. scopulorum, A. sepultipes, A. serenoi, A. sericoleucus, A. serpens, A. sesquiflorus, A. sheldonii, A. shevockii, A. shortianus, A. siliceus, A. simplicifolius, A. sinuatus, A. solitarius, A. sophoroides, A. soxmaniorum, A. spaldingii, A. sparsiflorus, A. spatulatus, A. speirocarpus, A. straturensis, A. striatiflorus, A. subcinereus, A. subvestitus, A. succumbens, A. tegetarioides, A. tener, A. tennesseensis, A. tephrodes, A. terminalis, A. tetrapterus, A. thurberi, A. tibetanus, A. tidestromii, A. tiehmii, A. titanophilus, A. toanus, A. toquimanus, A. tortipes, A. traskiae, A. tricarinatus, A. trichopodus, A. tridactylicus, A. troglodytus, A. tweedyi, A. tyghensis, A. umbellatus, A. umbraticus, A. uncialis, A. utahensis, A. vaccarum, A. vallaris, A. vexilliflexus, A. villosus, A. wardii, A. waterfallii, A. webberi, A. welshii, A. wetherillii, A. whitneyi, A. williamsii, A. wingatanus, A. wittmannii, A. woodruffii, A. wootonii, A. wrightii, A. xiphoides, A. yoderwilliamsii, A. zionis
Subordinate taxa
A. miser var. crispatus, A. miser var. decumbens, A. miser var. hylophilus, A. miser var. miser, A. miser var. oblongifolius, A. miser var. praeteritus, A. miser var. serotinus, A. miser var. tenuifolius
Name authority S. Watson: Botany (Fortieth Parallel), 69. (1871) Douglas in W. J. Hooker: Fl. Bor.-Amer. 1: 153. (1831)
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