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Robbins' milk-vetch

mourning milkvetch

Habit Plants clump-forming, slender to robust, 7–45(–60) cm, strigulose to pilose-villosulous; from superficial or somewhat subterranean caudex. Plants caulescent, (1–)3–24(–30) cm, strigulose.
Stems

usually ascending, rarely decumbent, 0–2 cm underground, strigulose to pilose-villosulous.

prostrate to ascending, strigulose.

Leaves

2.5–12 cm;

stipules 1.5–6 mm, papery at proximal nodes, herbaceous or submembranous at distal nodes;

leaflets (5 or)7–17, blades lanceolate to oblong, (3–)5–30(–32) mm, apex obtuse or emarginate, surfaces usually strigulose, sometimes villous-pilosulous, cinereous, glabrate, or glabrous abaxially, glabrous, glabrescent, or sparsely strigose adaxially.

(1.5–)3–14(–14.5) cm;

stipules distinct, 1–5 mm, papery-scarious at proximal nodes, subherbaceous at distal nodes;

leaflets 7–15, blades oblong-oblanceolate, elliptic, oval-oblong, linear-oblong, linear-elliptic, or linear-setaceous, 1.5–16 mm, apex obtuse, retuse, subacute, or emarginate, surfaces strigulose abaxially, strigulose or glabrous adaxially;

terminal leaflet sometimes decurrent distally, jointed to or continuous with rachis.

Racemes

(3–)5–25(–33)-flowered;

axis 1–18(–20) cm in fruit, elongating little after flowering, arising distal to middle of stem;

bracts 1–3.5 mm;

bracteoles usually 0.

(2–)5–18-flowered, flowers nodding;

axis (1.5–)3–17 cm in fruit;

bracts (0.8–)1–2.5 mm;

bracteoles usually 0.

Peduncles

incurved-ascending or erect, 3.5–21(–23) cm, usually surpassing subtending leaf, together with racemes usually shorter than stems.

incurved-ascending, (1.5–)3–16.5 cm.

Pedicels

0.5–3 mm.

(1.5–)2–6.5 mm.

Flowers

(6–)7.2–11.5 mm;

calyx 4–6.8 mm, strigulose, tube 3.2–4.5 mm, lobes subulate, 0.7–2.3 mm;

corolla usually purple, pink-purple, pink, lilac, lavender, or whitish, sometimes whitish with maculate keel;

wing apex obtuse;

keel 5.4–7.9 mm, shorter than wings.

6.3–13.4 mm;

calyx 3–7.6 mm, strigulose, tube 2.3–5.6 mm, lobes subulate, 0.7–2.6 mm;

corolla whitish or dirty white, sometimes veined, tipped, margined, or suffused with purple, or faintly tinged lavender;

keel 6–10 mm.

Legumes

pendulous, green or purplish, straight or slightly decurved, ellipsoid, obtusely 3-sided, faces slightly convex, flattened or depressed but not sulcate abaxially, 13–25 × 3.5–5.5 mm, subunilocular or semibilocular, papery-membranous, sparsely strigulose, hairs black or black and white;

valves inflexed as hyaline septum 0.2–2 mm wide;

stipe (0.5–)1.5–6.5 mm.

pendulous, green, purplish, or mottled, decurved or straight, linear-oblong, linear-oblanceoloid, or narrowly ellipsoid, compressed, ventral suture convex in profile or at least beak declined from body, 10–22 × 2.3–4.3 mm, unilocular or bilocular, thinly fleshy becoming papery or leathery, strigulose;

septum (0 or)0.6–2.7 mm wide;

stipe 0–2 mm, concealed within calyx when present.

Seeds

6–11.

10–29.

Astragalus robbinsii

Astragalus atratus

Distribution
from USDA
North America
[WildflowerSearch map]
[BONAP county map]
from USDA
w United States
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 8 (8 in the flora).

Astragalus robbinsii consists of a series of infraspecific taxa with two centers of dispersal in North America: Colorado to Alaska, and New England into eastern Canada. The distribution of three closely allied subordinate taxa within Vermont and New Hampshire is unmatched in the genus in North America. D. Isely (1998) questioned the taxonomic significance of the traditional varieties as recognized herein. The species is often confused in herbaria with A. alpinus, which has a keel longer than or as long as and wider than the wings (in A. robbinsii the keel is shorter than and little or no wider than the wings).

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

Varieties 4 (4 in the flora).

R. C. Barneby (1964) related that the main pattern underlying the complex racial differentiation in Astragalus atratus is one of northern and southern branches relating to the Snake-Humboldt divide in northeastern Nevada. Populations there and northward have subentire wing petals and unilocular fruits. Southward, the wings are toothed or lobed, and the fruit is nearly bilocular.

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

Key
1. Leaflet blade surfaces abaxially densely gray or white villous-pilosulous, hairs 0.6–0.8 mm; legume stipes 1.2–3 mm, septae 1.2–2 mm wide; s coastal Alaska.
var. harringtonii
1. Leaflet blade surfaces abaxially sparsely strigu­lose, cinereous, glabrous, or glabrate, hairs 0.2–0.6(–0.7) mm; legume stipes (0.5–)1.5–5(–6.5) mm, septae 0.2–1(–1.5) mm wide; not in s coastal Alaska.
→ 2
2. Legume stipes (1–)1.5–5(–6.5) mm; Alaska, New England, Nova Scotia, n Rocky Mountains.
→ 3
3. Stems 7–10 cm; racemes 5–11-flowered, axes 1–1.5 cm in fruit (barely elongated); legume stipes 5 mm; seeds 5 or 6; Mt. Roberts, near Juneau, Alaska.
var. morganiae
3. Stems 10–40(–60) cm; racemes (5–)7–21-flowered, axes (1–)3–18(–20) cm in fruit; legume stipes (1–)1.5–5(–6.5) mm; seeds (6 or)7–11.
→ 4
4. Legumes 10–15 mm, sparsely strigu­lose, beaks to 1 mm; corollas whitish; Vermont historically.
var. robbinsii
4. Legumes (10–)13–25 mm, sparsely or densely pubescent, beaks 0.8–3 mm; corollas pale purple, pink-purple, pink, or whitish and keel tip purple; widespread, including Vermont.
→ 5
5. Legumes sparsely strigose-pilosulous, beaks 0.8–1.5 mm; leaf­let blade surfaces uniformly strigu­lose abaxially, or glabrate through­out; Alaska, Canada, w United States, Maine and Vermont.
var. minor
5. Legumes sparsely strigulose, beaks 1.5–3 mm; leaflet blade surfaces cinereous abaxially, pubescent adax­ially (margins sparsely pubescent); local along Connecticut River in Vermont and New Hampshire.
var. jesupii
2. Legume stipes 0.5–3(–6.5) mm; coastal Labrador, adjoining Newfoundland, e Quebec to Alberta, northward to Northwest Territories, southward to New Mexico, including Maine and Vermont.
→ 6
6. Seeds 3–6; legumes 8–13 mm; Wallowa Mountains, ne Oregon.
var. alpiniformis
6. Seeds (6 or)7–10; legumes (8–)10–25 mm; not Oregon.
→ 7
7. Raceme axis 1.2–6(–8) cm in fruit; leaflet blade surfaces sparsely pubescent along margins adaxially or strigulose throughout; s Labrador, adjoining Newfoundland, Quebec.
var. fernaldii
7. Raceme axis (2–)3–18(–20) cm in fruit; leaflet blade surfaces glabrous or glabrate adaxially; not s Labrador, adjoining Newfoundland, and Quebec.
→ 8
8. Legumes (10–)13–25 mm, stipes (1–)1.5–5(–6.5) mm; racemes (5–)7–25(–33)-flowered, axes (2–)3–18(–20) cm in fruit; proximal stipules distinct or obscurely connate; not ne Nevada.
var. minor
8. Legumes (8–)10–15(–18) mm, stipes 0.5–1.4 mm; racemes remotely (3–)6–12-flowered, axes (2–)6–15 mm in fruit; proximal stipules connate 1/2 their length; East Humboldt and Ruby mountains, ne Nevada.
var. occidentalis
1. Legumes laterally compressed, bilocular, stipes 0–0.7 mm; Death Valley, Inyo County, California.
var. mensanus
1. Legumes ± dorsiventrally compressed, unilocu­lar or bilocular, stipes 0.3–2 mm; c Nevada to e Oregon and sw Idaho.
→ 2
2. Legumes sub-bilocular, leathery, septae 0.6–1.3 mm wide; terminal leaflets jointed to rachises; c, nc Nevada.
var. atratus
2. Legumes unilocular, leathery or papery, septae obsolete or to 0.2 mm wide; terminal leaflets jointed to or continuous with rachises; Idaho, Oregon, extreme ne Nevada.
→ 3
3. Leaflet blades narrowly oblong-oblanceolate to linear-oblong or oval, 3–13 mm, terminal leaflets jointed to rachises; legumes leathery; n side of Snake River Plains in Blaine, Camas, and Lincoln counties, Idaho.
var. inseptus
3. Leaflet blades linear-elliptic, 1.5–7(–10) mm, terminal leaflets continuous with rachises or reduced to slight dilation of rachis tips; legumes papery; e Oregon, extreme sw Idaho (Owyhee to Washington counties), ne Nevada.
var. owyheensis
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Astragalus > sect. Oroboidei Fabaceae > subfam. Faboideae > Astragalus > sect. Atrati
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. 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. 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. 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. 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. robbinsii var. alpiniformis, A. robbinsii var. fernaldii, A. robbinsii var. harringtonii, A. robbinsii var. jesupii, A. robbinsii var. minor, A. robbinsii var. morganiae, A. robbinsii var. occidentalis, A. robbinsii var. robbinsii
A. atratus var. atratus, A. atratus var. inseptus, A. atratus var. mensanus, A. atratus var. owyheensis
Synonyms Phaca robbinsii
Name authority (Oakes) A. Gray: Manual ed. 2, 98. (1856) S. Watson: Botany (Fortieth Parallel), 69, plate 11. (1871)
Web links