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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

leafy pea, leafy peavine, Oregon pea

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

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

angled, erect, sprawling, or climbing, basally branched 0–2 times, 4–8 dm.

Leaves

(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.

11–16 cm;

tendrils well developed;

stipules ovate to lanceolate, 20–30 × 10–30 mm, nearly equal to distal leaflets;

leaflets 10–16, scattered, blades ovate to lanceolate, 30–50 × 10–30 mm, surfaces glabrous.

Inflorescences

2–6-flowered, 2–10 cm.

8–12-flowered, 9–14 cm.

Flowers

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.

15–18 mm;

calyx lobes unequal, lateral lobes linear-triangular, equal to or longer than tube;

corolla blue-purple, banner erect, blade longer than claw, wings equal to keel;

ovary glabrous.

Legumes

25–45 × 6–10 mm.

40–70 × 4–9 mm.

2n

= 14.

Lathyrus lanszwertii

Lathyrus polyphyllus

Phenology Flowering Apr–Jul.
Habitat Openings in coniferous forests.
Elevation 0–1800 m. (0–5900 ft.)
Distribution
from USDA
w North America
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 5 (5 in the flora).

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

Lathyrus polyphyllus is known from in and west of the Cascade Range. Lathyrus ecirrhosus A. Heller (1904), not Philippi (1892), is an illegitimate name that pertains here.

(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. 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
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. lanszwertii, L. latifolius, L. littoralis, L. nevadensis, L. nissolia, L. ochroleucus, L. odoratus, L. palustris, L. pauciflorus, 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
Name authority Kellogg: Proc. Calif. Acad. Sci. 2: 150, fig. 44. (1863) Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 274. (1838)
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