sweet peas and vetchlings

genus Lathyrus

Member of vetches vs. vetchlings
legume family (family Fabaceae)
dicots (class Magnoliopsida)
flowering plants (subphylum Angiospermae)

Except for historical records that I'm ignoring, there are no other wild species of this genus in the bay area.

Key features:

number of flowers in inflorescence
number of leaflets per leaf
shape of tendril extending from leaf axis
width of wings or angles on stem
bristle extending on axis beyond flower
length of calyx tube vs. lobes

many flowers, many leaflets

pacific pea
Lathyrus vestitus

8–15 flowers in inflorescence
generally 8–12 leaflets per leaf
leaf axis ends in branched, coiled tendril
stem often sharply angled or flanged, not winged (angles or flanges < 1 mm wide)
corolla 14–20 mm, pale lavendar to dark purple or wine red or white, depending on variety

photo

delta tule pea
Lathyrus jepsonii

6–15 flowers in inflorescence
10–16 leaflets per leaf
leaf axis ends in branched, coiled tendril
stem winged (wings ± ≥ 1 mm wide)
corolla 15–20 mm, generally pink to pink-purple
L. j. var. californicus is a smaller plant which is sometimes hairy.
L. j. var. jepsonii can exceed two meters in height and is hairless, a rare variety which grows in the estuary habitat of the Sacramento-San Joaquin River Delta, the origin of the common name delta tule pea.

silky beach pea
Lathyrus littoralis

1–many flowers in inflorescence
0–16 leaflets per leaf
leaf axis ends in short bristle (not coiled or branched tendril)
stem angled or flanged, not winged
corolla 8–30 mm, pink-purple or pale, occasionally white or yellow
Ecology: open coastal dunes

many flowers, two leaflets

broad-leaved sweet pea
Lathyrus latifolius

4–15 flowers in inflorescence
2 leaflets per leaf
stem with wings often ≥ 2 mm wide
corolla 20–25 mm
calyx tube > lobes

sweet pea
Lathyrus odoratus

2–4 flowers in inflorescence
stem with wings < 2 mm wide
2 leaflets, 3–6 cm, ovate to narrowly elliptic
corolla 20–30 mm, white or pale pink to purple
calyx tube ± = lobes

tangier pea
Lathyrus tingitanus

2–3 flowers in inflorescence
stem with wings < 2 mm wide
2 leaflets, 2–6 cm, lanceolate to widely ovate
corolla 25–30 mm, salmon to red-purple
calyx tube > lobes

one or two flowers

torrey’s pea
Lathyrus torreyi

1–2 flowers in inflorescence
10–15 leaflets per leaf
leaf axis ends in bristle or not (not coiled or branched tendril)
corolla 8–10 mm, lilac to pale purple-blue

hairy vetchling
Lathyrus hirsutus

1–2 flowers in inflorescence
2 leaflets per leaf
inflorescence axis not extended beyond flower
corolla 9–14 mm, pink to blue-purple or 2-colored
calyx tube ± = lobes

one flower, two leaflets

red vetchling
Lathyrus cicera

1 flower in inflorescence
2 leaflets per leaf
stipules broad, lanceolate
corolla 10–15 mm, red
inflorescence axis terminates at flower pedicel
calyx tube ≪ lobes

photo

grass pea
Lathyrus sphaericus

1 flower in inflorescence
2 leaflets per leaf
stipules small and narrow
corolla 8–14 mm, red
inflorescence axis continues as bristle beyond flower pedicel branch point
calyx tube ± ≤ lobes

angled pea
Lathyrus angulatus

1 flower in inflorescence
2 leaflets per leaf
corolla 9–12 mm, lavender or purple
inflorescence axis extended as bristle beyond flower
calyx tube ± ≤ lobes

indian pea
Lathyrus sativus

1 flower in inflorescence
2 leaflets per leaf
stem winged[?]
corolla [usually?] blue, but possibly red-purple, red, pink, or white

Toxicity of pea, everlasting; singletary pea; wild pea (Lathyrus spp.):
4 – Ingestion of these plants, especially in large amounts, is expected to cause serious effects to the heart, liver, kidneys or brain. If ingested in any amount, call the poison center immediately.

5 observed taxons / 7 unobserved taxons / 1 key

Chris’s observations: 77 (60 are research grade)

Locations:

Henry Coe SP: 5
Russian Ridge OSP: 5
Sierra Azul OSP: 5
Almaden Quicksilver CP: 4
Calero CP: 4
Nisene Marks SP: 4
Castle Rock SP: 3
San Pedro Valley CP: 3
Stevens Creek CP: 3
Sweeney Ridge National Recreation Area: 3
Waterdog Lake & Open Space: 3
Bear Creek Redwoods OSP: 2
Coyote Valley OSP: 2
Edgewood Park & Natural Preserve: 2
El Corte de Madera OSP: 2
Golden Gate National Recreation Area: 2
Sanborn CP: 2
Santa Teresa CP: 2
Skyline Ridge OSP: 2
Alum Rock Park, San Jose
Big Basin SP
Butano SP
Coal Creek OSP
Dry Creek Pioneer RP
Joseph D. Grant CP
Lake Chabot RP
Lexington Reservoir CP
Monte Bello OSP
Mt. Diablo SP
Mt. Madonna SP
Mt. Tamalpais Watershed
Murray Ranch SP
Purisima Creek Redwoods OSP
San Bruno Mountain State & County Park
Skyline Blvd.
Sunol Wilderness RP
Wilder Ranch SP
Windy Hill OSP

Months:

Jan.: 1
Feb.: 4
Mar.: 13
Apr.: 17
May: 19
Jun.: 10
Jul.: 6
Aug.: 5
Sep.: 1
Oct.: 0
Nov.: 1

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Taxon info: iNaturalist – Calflora – Jepson eFlora – FNA

Bay Area species: iNaturalist – Calflora