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Missouri milk-vetch

Pursh's milk-vetch, Pursh's sheeppod, woolly-pod milk-vetch

Habit Plants sometimes loosely tuft-forming, shortly caulescent, subacaulescent, or caulescent, 5–15(–20) cm, strigose or strigulose, hairs malpighian; from subterranean caudex. Plants tuft-forming, acaulescent, subacaulescent, or shortly caulescent, 4.5–13 cm, usually villous to villous-tomentose, sometimes appearing white or gray, hairs basifixed; from branched, superficial caudex, branches with thatch.
Stems

prostrate and radiating, to 15(–20) cm, internodes often concealed by stipules, strigose or strigulose.

usually obscured by stipules, or internodes to 2 cm, villous to villous-tomentose.

Leaves

(2–)4–14 cm;

stipules sometimes connate-sheathing at proximal nodes (vars. humistratus and missouriensis), (2–)3–9 mm, firm or submembranous becoming scarious or papery;

leaflets (5–)11–17(–21), blades elliptic to obovate, 3.5–13(–17) mm, apex acute, apiculate, or obtuse, surfaces strigose to strigulose.

1–12(–15) cm;

stipules (2.5–)3–15 mm, membranous;

leaflets (3 or)5–17(–21), blades obovate, obovate-cuneate, elliptic to oblanceolate, or rhombic-elliptic, 2–14(–20) mm, apex usually acute, subacute, acuminate, or obtuse, rarely truncate-emarginate, surfaces densely villous.

Racemes

(3–)4–15-flowered, flowers ascending to spreading;

axis (0.5–)1–4 cm in fruit;

bracts 2.5–8 mm;

bracteoles 0–2.

1–11-flowered, flowers ascending;

axis 0.3–2(–4) cm in fruit;

bracts 2–9 mm;

bracteoles 0.

Peduncles

ascending, (1.5–)3.5–11 cm.

ascending or erect, decumbent in fruit, 1.5–10.5 cm.

Pedicels

1–3.5 mm.

1–5 mm.

Flowers

9.5–22(–24) mm;

calyx purple-tinged, cylindric or deeply campanulate, 5–13(–14.3) mm, strigulose, tube 4.1–10 mm, lobes subulate, (0.7–)1.4–4.5(–5.3) mm;

corolla usually pink-purple, purple, lavender, or violet-red, rarely white;

banner recurved through 45°;

keel 8.9–17.3(–18.5) mm.

19–25(–27) mm;

calyx cylindric, cylindro-campanulate, or campanulate, (5.5–)6–16(–19) mm, villous-pilose, tube (4–)4.5–12(–13.6) mm, lobes subulate, 1–6(–7) mm;

corolla white, cream, purple, or pink-purple;

banner recurved through 40°;

keel 8–21.2(–22.5) mm.

Legumes

usually persistent, ascending or descending, brownish becoming black, straight or slightly incurved, subsymmetrically or obliquely oblong, oblong-ellipsoid, or ellipsoid, subterete, or dorsiventrally or ± laterally compressed, (11–)14–28(–30) × (4–)5–9(–10) mm, unilocular or subunilocular, distinctly beaked, fleshy becoming stiffly leathery or subligneous, walls much less than 1 mm thick, strigulose, strigose, or glabrous.

initially ascending (humistrate), brownish, not mottled or spotted, incurved, ovoid, ovoid-ellipsoid, or lanceoloid-ellipsoid, dorsiventrally compressed, 7–26(–30) × 3.5–11(–13) mm, unilocular, fleshy becoming leathery, mostly shaggy-villous, sometimes tomentose or villous-hirsute, hairs 1.6–4(–5) mm, often concealing surface;

sessile or subsessile, or gynophore 0.5+ mm.

Seeds

(33–)35–55(or 56).

14–38(–46).

2n

= 22.

Astragalus missouriensis

Astragalus purshii

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

Varieties 4 (4 in the flora).

From the central Canadian provinces to trans-Pecos Texas and western Iowa, Astragalus missouriensis is remarkably uniform morphologically. In the Four Corners region of the Southwest, it has undergone considerable differentiation.

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

Varieties 8 (8 in the flora).

The geographic distribution of Astragalus purshii, forming a relatively large triangle in western North America, from southwestern Canada to southern California, northeastward to western North Dakota, makes it the most widely distributed of all astragali with woolly fruits. The case for specific status for such entities as A. inflexus and A. utahensis may be little stronger than that for several of the taxa included within A. purshii (D. Isely 1998). L. Abrams (1944b) often gave an inclusive name of woolly-pod to all of the fuzzy-podded species, sometimes sheep-pod. For consistency they are all called milkvetch here. Isely gave a synopsis that helped to distinguish other woolly fruited species. The treatment of R. C. Barneby (1964) is followed here, and his key to varieties is largely followed.

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

Key
1. Calyces 5–5.8 mm; banners 9.5–11.8 mm; keel 8.9–10.6 mm; wc New Mexico, ne Arizona.
var. mimetes
1. Calyces 6–13(–14.3) mm; banners 14.5–22(–24) mm; keel (11.5–)12.8–17.3(–18.5) mm; Prairie Provinces southward to Arizona and Texas, eastward to Iowa and Minnesota.
→ 2
2. Legumes subsymmetrically oblong-ellipsoid, ± straight, initially subterete or ± dorsiven­trally compressed, at maturity ± laterally compressed and obtuse-angled; Prairie Provinces south­ward to Arizona and Texas, eastward to Iowa and Minnesota.
var. missouriensis
2. Legumes ellipsoid or oblong-ellipsoid, lunately incurved, dorsiventrally com­pressed, apices obcompressed proximal to incurved beak; Four Corners area.
→ 3
3. Plants subacaulescent to shortly cau­lescent; stems to 10 cm; racemes 4–8-flowered; Apache County, Arizona, Garfield to La Plata and Montezuma coun­ties, Colorado, San Juan County, New Mexico, Grand and San Juan coun­ties, Utah.
var. amphibolus
3. Plants caulescent; stems 10–15(–20) cm; racemes 9–12-flowered; Archuleta, Hins­dale, and La Plata counties, Colorado, adja­cent Rio Arriba County, New Mexico.
var. humistratus
1. Calyces (5.5–)6–10.1 mm; banners 9–16.5 mm; keel 8–13 mm.
→ 2
2. Racemes (3–)5–11-flowered; leaflets (7 or)9–15(or 17); sw Idaho.
var. ophiogenes
2. Racemes 1–5(–7)-flowered; leaflets (3 or)5–9(or 11); California, sw Idaho, nw Nevada, and along foothills and plains adjacent to e slope of Cascades in Oregon.
→ 3
3. Legumes incurved only in beak; seeds 24–32; San Bernardino Mountains and Sierra Nevada, California, w Nevada.
var. lectulus
3. Legumes arched throughout, at least through 0.5–1 spiral; seeds 14–20; plains of ne California to c Oregon, sw Idaho, and nw Nevada.
var. lagopinus
1. Calyces (8–)9–16(–19) mm; banners (14.6–)15.4–25(–26) mm; keel (11.5–)12.4–21.2(–22.5) mm.
→ 4
4. Corollas mostly white or cream (keel tip maculate), rarely banners and wings tipped dull, pale bluish purple; widespread from California and British Columbia eastward to North Dakota and Colorado.
var. purshii
4. Corollas purple or pink-purple throughout; British Columbia to s California (cis- and transmontane), sw Montana, and sc Nevada.
→ 5
5. Banners (14.6–)19–25(–26.5) mm; keel (11.5–)12.4–21(–22.5) mm.
→ 6
6. Plants acaulescent or subacaulescent; leaflets (5 or)7 or 9(or 11), blades obovate, obovate-cuneate, or broadly elliptic, apices obtuse or truncate; ec Idaho, sw Montana.
var. concinnus
6. Plants shortly caulescent or subacau­lescent; leaflets (3 or)5–17(–21), blades obovate-cuneate, oblanceolate, nar­rowly elliptic or elliptic-oblanceolate, apices usually acute, subacute, or short-acuminate, rarely obtuse; British Columbia, California, Idaho, Nevada, Oregon, Utah, Washington.
→ 7
7. Legumes not or very shallowly sulcate ventrally; leaflets (3 or)5–13(–17), blades usually obovate-cuneate or oblanceolate, rarely elliptic-oblanceolate, apices usually acute or subacute, rarely obtuse; racemes 3–11-flowered; banners (14.6–)15.4–25 mm; cis- and trans­montane California, w Nevada, and Oregon.
var. tinctus
7. Legumes strongly depressed-sulcate ventrally in proximal 1/2; leaflets (7 or)9–15(or 17), blades usually narrowly elliptic, rarely elliptic-oblanceolate, apices usually acute or short-acuminate; racemes 2–5(–10)-flowered; banners 19–25(–26.5) mm; Oregon and British Columbia eastward to Utah.
var. glareosus
5. Banners 11.5–18(–25) mm; keel 10.2–15(–20.8) mm.
→ 8
8. Legumes strongly sulcate ventrally in proximal 1/2; c Nevada.
var. pumilio
8. Legumes not or shallowly sulcate ventrally; ne California, sw Idaho, nw Nevada, se Oregon.
→ 9
9. Legumes 13–23(–27) mm; racemes with relatively short (subcapitate) flowering axes; ne California, nw Nevada, e Oregon.
var. tinctus
9. Legumes 8–13 mm; racemes with relatively long flowering axes; along Owyhee, Snake, and lower Bruneau rivers, se Oregon and sw Idaho.
var. ophiogenes
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Astragalus > sect. Argophylli Fabaceae > subfam. Faboideae > Astragalus > sect. Argophylli
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. 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
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. 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. missouriensis var. amphibolus, A. missouriensis var. humistratus, A. missouriensis var. mimetes, A. missouriensis var. missouriensis
A. purshii var. concinnus, A. purshii var. glareosus, A. purshii var. lagopinus, A. purshii var. lectulus, A. purshii var. ophiogenes, A. purshii var. pumilio, A. purshii var. purshii, A. purshii var. tinctus
Name authority Nuttall: Gen. N. Amer. Pl. 2: 99. (1818) Douglas in W. J. Hooker: Fl. Bor.-Amer. 1: 152. (1831)
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