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grass-leaf pea

aspen peavine, lanszwert's pea, lanszwert's vetchling, Nevada pea, Nevada peavine, Nevada sweet pea, pinewood peavine, Rocky Mountain sweetpea, thick-leaf pea, thick-leaf peavine

Habit Herbs perennial, from rhizome or woody rootstock, glabrous. Herbs perennial, from rhizome, glabrous or sparsely pubescent.
Stems

angled, sprawling or climbing, sometimes branched at flowering nodes, 2–6 dm.

angled, erect, sprawling, or climbing, basally branched 0–4 times, 1–8 dm.

Leaves

5–9 cm;

tendrils usually well developed;

stipules lanceolate to linear, 8–12 × 1–5 mm, much smaller than leaflets;

leaflets 4–8, scattered, blades usually linear, rarely lanceolate, 30–80 × 1–20 mm, surfaces glabrous.

(0.5–)1–8 cm;

tendrils mucronate to well developed;

stipules linear to lanceolate, 5–25 × 1–6 mm, much smaller than leaflets;

leaflets 2–10, scattered, blades lanceolate or linear, 20–70 × 2–20 mm, surfaces glabrous or sparsely pubescent.

Inflorescences

5–8-flowered, 10–18 cm.

2–6-flowered, 2–10 cm.

Flowers

8–15 mm;

calyx lobes subequal, lateral lobes deltate, shorter than tube;

corolla white to blue-orchid, banner erect, blade equal to claw, wings equal to keel;

ovary glabrous.

7–15 mm;

calyx lobes unequal, lateral lobes deltate, shorter than tube;

corolla white or blue-purple, banner erect, blade equal to claw, wings equal to keel;

ovary glabrous.

Legumes

30–50 × 4–8 mm.

25–45 × 6–10 mm.

2n

= 14.

Lathyrus graminifolius

Lathyrus lanszwertii

Phenology Flowering Apr–Aug.
Habitat Slopes of ponderosa pine, mixed conifer, spruce-fir and oak-juniper forests.
Elevation 1000–2800 m. (3300–9200 ft.)
Distribution
from FNA
AZ; NM; TX; Mexico (Chihuahua, Sonora)
[WildflowerSearch map]
[BONAP county map]
from USDA
w North America
[WildflowerSearch map]
[BONAP county map]
Discussion

Lathyrus graminifolius is known from the eastern half of Arizona to the western two-thirds of New Mexico and in trans-Pecos Texas.

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

Varieties 5 (5 in the flora).

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

Key
1. Stems (2–)3–8 dm, usually climbing, sometimes sprawling or erect; tendrils well developed, usually branched.
→ 2
2. Leaflets 8–10; corollas blue-purple; California northward to Washington, eastward to Colorado and Wyoming.
var. lanszwertii
2. Leaflets 6–8; corollas white; w Colorado, c Utah, Wyoming.
var. pallescens
1. Stems 1–3(–4) dm, usually erect (sometimes var. bijugatus sprawling or climbing); tendrils reduced to simple bristles less than 1 cm.
→ 3
3. Leaflets 2–4; e Washington, adjacent Idaho, Montana, British Columbia.
var. bijugatus
3. Leaflets 4–8; California northward to sc Washington and eastward to New Mexico, Colorado, and Wyoming.
→ 4
4. Flowers 7–10 mm; California, Nevada, Oregon, Washington.
var. aridus
4. Flowers 10–15 mm; Arizona, Colorado, New Mexico, Utah, Wyoming.
var. leucanthus
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Lathyrus Fabaceae > subfam. Faboideae > Lathyrus
Sibling taxa
L. angulatus, L. aphaca, L. biflorus, L. brachycalyx, L. brownii, L. cicera, L. decaphyllus, L. delnorticus, L. eucosmus, L. glandulosus, L. grimesii, L. hirsutus, L. hitchcockianus, L. holochlorus, L. japonicus, L. jepsonii, L. laetivirens, L. lanszwertii, L. latifolius, L. littoralis, L. nevadensis, L. nissolia, L. ochroleucus, L. odoratus, L. palustris, L. pauciflorus, L. polyphyllus, L. pratensis, L. pusillus, L. rigidus, L. sphaericus, L. splendens, L. sulphureus, L. sylvestris, L. tingitanus, L. torreyi, L. tracyi, L. tuberosus, L. venosus, L. vestitus
L. angulatus, L. aphaca, L. biflorus, L. brachycalyx, L. brownii, L. cicera, L. decaphyllus, L. delnorticus, L. eucosmus, L. glandulosus, L. graminifolius, L. grimesii, L. hirsutus, L. hitchcockianus, L. holochlorus, L. japonicus, L. jepsonii, L. laetivirens, L. latifolius, L. littoralis, L. nevadensis, L. nissolia, L. ochroleucus, L. odoratus, L. palustris, L. pauciflorus, L. polyphyllus, L. pratensis, L. pusillus, L. rigidus, L. sphaericus, L. splendens, L. sulphureus, L. sylvestris, L. tingitanus, L. torreyi, L. tracyi, L. tuberosus, L. venosus, L. vestitus
Subordinate taxa
L. lanszwertii var. aridus, L. lanszwertii var. bijugatus, L. lanszwertii var. lanszwertii, L. lanszwertii var. leucanthus, L. lanszwertii var. pallescens
Synonyms L. palustris var. graminifolius
Name authority (S. Watson) T. G. White: Bull. Torrey Bot. Club 21: 454. (1894) Kellogg: Proc. Calif. Acad. Sci. 2: 150, fig. 44. (1863)
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