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mat milk vetch, mountain kentrophyta

kentrophyta, Nuttall's kentrophyta, spiny milk-vetch, thistle milk-vetch

Habit Plants prostrate, cushion-forming, 5–40(–50) cm wide. Plants often mat- or cushion-forming, sometimes suffruticose basally, 15–45 cm, usually strigulose, sometimes villosulous or villous, hairs basifixed or malpighian; from caudex bearing stolonlike, creeping stems.
Stems

and herbage densely to sparsely strigulose, villosulous, or villous, hairs basifixed.

prostrate, decumbent, spreading, or erect, compact to elongate, usually strigulose, sometimes villosulous or villous.

Leaves

(0.2–)0.4–1.5(–2) cm;

stipules 2–7 mm;

leaflets (3 or)5–9, blades 1–9 mm, surfaces pubescent or adaxially glabrous or medially glabrescent.

(0.2–)0.4–2.6 cm;

stipules connate-sheathing, sometimes distinct at distal nodes, 1–12 mm, scarious throughout, or herbaceous becoming papery, or stiff and spiny, apex acuminate, spinulose, or callous-mucronate;

leaflets (3 or)5–9, blades decurrent, continuous with rachis, linear to narrowly elliptic or lanceolate, (1–)3–15(–17) mm, apex spinulose, surfaces usually strigose, rarely glabrous adaxially.

Racemes

1–3-flowered, flowers declined;

axis to 0.5 cm in fruit;

bracts 0.8–3.5 mm;

bracteoles 0.

Peduncles

0–1.5(–3) cm.

subobsolete or 0.1–0.6(–3) cm.

Pedicels

0.5–2 mm.

Flowers

(3.9–)4.5–8(–9.2) mm;

calyx (2–)2.4–5.7(–7) mm, tube 1.2–2.6(–2.8) mm, lobes subulate to setaceous, (0.5–)1.9–2.6(–4.2) mm;

corolla usually purple or purplish, sometimes white and keel tip pink or purplish.

(3.9–)4–10 mm;

calyx (2–)2.4–8.3 mm, strigose, tube 1.2–2.8(–3.3) mm, lobes subulate, setaceous, or spinulose, (0.5–)1.4–5 mm;

corolla usually pink-purple or whitish, sometimes pink-, lilac-, or purple-tinged;

banner recurved through 45°;

keel 3–6 mm.

Legumes

ellipsoid or oblong-ellipsoid, (3–)4–8(–9) × (0.6–)2–2.5 mm.

declined or spreading, stramineous, straight or slightly curved, ellipsoid to oblong-ellipsoid, lenticular, ovoid, ovoid-lenticular, lanceoloid-ellipsoid, or lanceoloid-acuminate, laterally compressed, 3–10 × (0.6–)1.4–4 mm, papery, strigose;

sessile.

Seeds

(3–)5–8.

2–8.

2n

= 24.

Astragalus kentrophyta var. tegetarius

Astragalus kentrophyta

Phenology Flowering Jun–Sep.
Habitat Ridgetops, breaks, alpine shrub and tundra with Phlox, Geum rossii, other forbs, grasses, less commonly with shrubs and trees, often in barrens.
Elevation 2000–3700 m. (6600–12100 ft.)
Distribution
from FNA
CA; CO; ID; MT; NM; NV; OR; UT; WY
[BONAP county map]
from USDA
w North America
[WildflowerSearch map]
[BONAP county map]
Discussion

The moderately large, usually purplish flowers borne just above the mat of foliage set var. tegetarius apart and make it one of the showiest phases of the species.

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

Varieties 9 (9 in the flora).

The varieties of Astragalus kentrophyta are distinguished from other astragali by the few leaflets continuous with the leafstalk while blades are simultaneously apically mucronate or spinulose, and by their racemes, usually subsessile in leaf axils, bearing one to three small flowers. There are two major groups: alpine or upper elevation, prostrate-matted to pulvinate-depressed plants, usually with bright purple flowers and basifixed hairs, with five to eight seeds; and lower elevation forms that range from prostrate to bushy and ascending, with white or lavender flowers, hairs sometimes malpighian, and two to five ovules. With the exception of the widespread var. tegetarius, the varieties are largely allopatric.

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

Key
1. Hairs basifixed; seeds (3–)5–8; corollas purple, purplish, or whitish and keel purple or pink- or purplish-tipped.
→ 2
2. Leaflets (3–)5–9, blades 1–9 mm; plants form­ing cushions 5–40(–50) cm wide; widespread, extending into California only to Inyo and White mountains and c High Sierra Nevada.
var. tegetarius
2. Leaflets 3(–7), blades 3–7 mm; plants forming cushions to 15 cm wide; sc Sierra Nevada, California.
var. danaus
1. Hairs malpighian or basifixed; seeds 2–4(–8); corollas whitish, keel apices sometimes pink or lilac-tinged or purplish (except pink-purple in var. coloradoensis, rarely in var. elatus).
→ 3
3. Calyces 6–8.3 mm, lobes 3.4–5 mm; legumes (5–)7–10 × 2.8–4 mm; seeds 4–8; canyons of Colorado River in nc Arizona and sc Utah.
var. coloradoensis
3. Calyces 2.4–5.2 mm, lobes 0.7–3 mm; legumes 3–7(–7.5) × 1.4–3.8 mm; seeds 2–4; California to Alberta, eastward to New Mexico and South Dakota.
→ 4
4. Legumes ovoid-lenticular, ovoid, or len­ticular.
→ 5
5. Stipules uniform, connate to 1/2 their lengths, spinulose; calyx lobes 0.7–1.5 mm; n New Mexico.
var. neomexicanus
5. Stipules dimorphic, those at most proximal nodes connate into short, bidentate sheath, those at distal nodes longer, connate at base only, lanceolate or lanceolate-acuminate, often without spines; calyx lobes 1.4–3 mm; North Dakota west to Alberta, southward to Colorado and Oregon.
→ 6
6. Leaflet blades glabrous or glabres­cent adaxially, pubescent abaxially, hairs basifixed or obscurely mal­pighian; legumes (3.5–)4–7 × 2.4–3.8 mm; s Wyoming east of Con­tinental Divide to Alberta and Sas­katchewan, southward to Col­orado, South Dakota, and w Nebraska.
var. kentrophyta
6. Leaflet blades pubescent, hairs mal­pighian; legumes 3–4.5 × 1.4–2 mm; sw Wyoming, ne Utah to se Oregon.
var. jessiae
4. Legumes ovoid-acuminate, lanceoloid, or lanceoloid-acuminate.
→ 7
7. Plants usually erect or assurgent, rarely trailing, often bushy, sometimes mat-forming; Arizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming.
var. elatus
7. Plants prostrate, mat- or cushion-forming; California, e, c Nevada, Oregon, se Washington.
→ 8
8. Hairs basifixed; calyx lobes 2.3–3 mm; Oregon, se Washington.
var. douglasii
8. Hairs malpighian; calyx lobes 1.8–2.6 mm; California, Nevada.
var. ungulatus
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Astragalus > sect. Ervoidei > Astragalus kentrophyta Fabaceae > subfam. Faboideae > Astragalus > sect. Ervoidei
Sibling taxa
A. kentrophyta var. coloradoensis, A. kentrophyta var. danaus, A. kentrophyta var. douglasii, A. kentrophyta var. elatus, A. kentrophyta var. jessiae, A. kentrophyta var. kentrophyta, A. kentrophyta var. neomexicanus, A. kentrophyta var. ungulatus
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. 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. kentrophyta var. coloradoensis, A. kentrophyta var. danaus, A. kentrophyta var. douglasii, A. kentrophyta var. elatus, A. kentrophyta var. jessiae, A. kentrophyta var. kentrophyta, A. kentrophyta var. neomexicanus, A. kentrophyta var. tegetarius, A. kentrophyta var. ungulatus
Synonyms A. tegetarius, A. aculeatus, A. kentrophyta subsp. implexus, A. kentrophyta var. implexus, A. kentrophyta var. rotundus, A. montanus var. rotundus, A. montanus var. tegetarius, A. tegetarius var. implexus, A. tegetarius var. rotundus, Homalobus aculeatus, H. tegetarius, H. wolfii, Kentrophyta aculeata, K. minima, K. rotunda, K. tegetaria, K. wolfii, Tragacantha tegetaria Kentrophyta montana
Name authority (S. Watson) Dorn: Vasc. Pl. Wyoming, 297. (1988) A. Gray: Proc. Acad. Nat. Sci. Philadelphia 15: 60. (1863)
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