pepperweeds

(peppergrasses)
genus Lepidium

Member of mustard family (family Brassicaceae)
dicots (class Magnoliopsida)
flowering plants (subphylum Angiospermae)

Except for old historical records and extremely rare examples that I don't expect to encounter, there are no other wild species of this genus in the bay area.

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Key features:

• woody caudex or stem base or not
• basal leaf shape
• middle and distal cauline leaf shapes
• inflorescence shape
• pedicel length, flattened or not
• sepals persistent or not
• petal length, abaxially hairy or glabrous
• number of stamens
• fruit length and shape
• valve tubercled or not, net-veined or not

Petals and fruit can co-exist, even on the same plant, so look around for both.

veiny pepperweed
Lepidium oblongum

• annual
• basal leaves not in a rosette, 1–2-pinnately lobed
• mid-cauline leaves pinnately lobed, base lobed or not
• inflorescence elongated
• petals < 1 mm, white, stamens 2
• fruit 2.2–3.5 mm, roundish, flat, tip winged, notch 0.2–0.3 mm
• valve not veined
• very rare

field peppergrass
Lepidium campestre

• annual
• basal leaves in a rosette, entire to pinnately lobed
• mid-cauline leaf bases lobed or sagittate
• inflorescence much elongated
• petals 1.5–2.5 mm, white, stamens 6
• fruit 5–6 mm, roundish, broadly winged at tip, notch 0.4–0.6 mm
• valve not veined
• very rare

lens-podded hoary cress
Lepidium chalepense

• perennial herb, rhizomed
• basal leaves not in a rosette, entire
• mid-cauline leaf bases clasping or lobed, ± dentate or entire
• inflorescence in a panicle, elongated
• petals 3–5 mm, white, stamens 6
• fruit 3.5–5.8 mm, roundish, inflated, tip wingless, no notch
• valve not veined
• rare

lesser swine-cress
Lepidium didymum

• annual
• basal leaves not in a rosette, 1–2-pinnately divided, lobes entire to lobed
• mid-cauline leaves gradually reduced and less divided distally, lobes entire to serrate
• no cauline leaf bases lobed or sagittate
• inflorescence elongated
• petals 0.4–0.5 mm, white, stamens 2
• fruit 1.3–1.7 mm, spectacle-shaped, flat, wingless, notch 0.2–0.4 mm
• valve tubercled, strongly veined
• all others are not tubercled or ridged
• uncommon

upright pepperweed
Lepidium strictum

• annual
• basal leaves not in a rosette, 2-pinnately lobed
• mid-cauline leaves pinnately lobed, lobes entire; base tapered
• no cauline leaf bases lobed or sagittate
• inflorescence crowded
• sepals 0.7–1 mm, persistent
• petals 0.2–0.5 mm, white, stamens 2
• fruit 2.5–3.3 mm, roundish, flat, tip winged, notch 0.3–0.6 mm
• valves prominently net-veined
• uncommon

virginia pepperweed
Lepidium virginicum

• annual
• basal leaves not in a rosette, pinnately lobed to dentate
• mid-cauline leaves entire to serrate, lobed, or divided; base tapered
• no cauline leaf bases lobed or sagittate
• inflorescence much elongated
• sepals 0.7–1 mm, deciduous
• petals 1–2.5 mm, white, stamens 2
• fruit 2.5–3.5 mm, roundish, tip winged, notch 0.2–0.5 mm
• valves not veined
• very rare

sharp-pod pepper-grass
Lepidium oxycarpum

• annual
• basal leaves not in a rosette, entire or pinnately lobed, early-deciduous
• mid-cauline lines 1–3 mm, base tapered
• no cauline leaf bases lobed or sagittate
• inflorescence elongated
• pedicel cylindric or ± flattened
• petals 0, stamens 4
• fruit 2.4–3.6 mm, roundish, flat, tip winged, notch 0.3–0.8 mm, V-shaped
• valves net-veined
• rare

wayside pepper grass
Lepidium pinnatifidum

• annual
• basal leaves not in a rosette, dentate or pinnately lobed, early-deciduous
• mid-cauline lines 1–3.3 mm, base tapered
• no cauline leaf bases lobed or sagittate
• inflorescence in a panicle, elongated
• pedicel cylindric
• petals 0.4–0.6 mm, white, stamens 4
• fruit 1.8–2 mm, roundish, flat, tip wingless, notch to 0.1 mm
• valves not veined
• very rare

san diego pepperweed
Lepidium latipes

• annual
• basal leaves not in a rosette, entire, dentate, or pinnately divided, early-deciduous
• mid-cauline leaves similar, smaller, base tapered
• no cauline leaf bases lobed or sagittate
• inflorescence compact, cylindric to head-like, elongated or not
• pedicel strongly flattened
• sepals 1.1–1.4 mm, persistent
• petals 1.9–3 mm, ± green, hairy abaxially, margin fringed, stamens 4
• fruit 5–7 mm, roundish, tip winged, notch 1.4–2.8 mm
• valve strongly net-veined
• rare

net pepper grass
Lepidium acutidens

• annual
• basal leaves not in a rosette, linear or pinnately divided, early-deciduous
• mid-cauline leaves linear, base tapered
• no cauline leaf bases lobed or sagittate
• inflorescence unknown [not elongated?]
• pedicel strongly flattened, appressed, 3–4.2 mm
• sepals 0.7–1.1 mm, not persistent
• petals 0, stamens 4
• fruit 4–6 mm, roundish, flat, tip winged, notch 1–2 mm, V-shaped
• valve strongly net-veined
• rare

alkali pepperweed
Lepidium dictyotum

• annual
• basal leaves not in a rosette, pinnately lobed or divided, early-deciduous
• mid-cauline leaves linear, base tapered
• no cauline leaf bases lobed or sagittate
• inflorescence elongated
• pedicel strongly flattened, appressed, 1.9–2.5 mm
• sepals 0.7–1.1 mm, not persistent
• petals 0, stamens 4
• fruit 2.5–3.5 mm, roundish, flat, tip winged, notch 0.5–0.7 mm, U-shaped
• valve strongly net-veined
• rare

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3 observed taxons / 11 unobserved taxons / 1 key

Chris’s observations: 38 (24 are research grade)

Locations:

• Calero CP: 9
• Coyote Lake / Harvey Bear Ranch CP: 6
• Joseph D. Grant CP: 5
• Máyyan 'Ooyákma Coyote Ridge OSP: 2
• Pacheco SP: 2
• Russian Ridge OSP: 2
• Sunol Wilderness RP: 2
• Bay Trail
• Coyote Hills RP
• Ed R. Levin CP
• Edgewood Park & Natural Preserve
• Garin RP
• Henry Coe SP
• Mission Peak RP
• Pleasanton Ridge RP
• Rancho Cañada del Oro OSP
• Santa Teresa CP

Months:

• Jan.: 2
• Feb.: 1
• Mar.: 12
• Apr.: 16
• May: 5
• Jun.: 1
• Jul.: 1

For more details, use advanced search.

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Taxon info: iNaturalist – Calflora – Jepson eFlora – FNA

Bay Area species: iNaturalist – Calflora