sow thistles

genus Sonchus

Member of yellow dandelion-like flowers
lettuce, chicory, dandelion, and salsify tribe (tribe Cichorieae)
thistles
sunflower family (family Asteraceae)
dicots (class Magnoliopsida)
flowering plants (subphylum Angiospermae)

There are no other wild species of this genus in the bay area.

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“Stem distally branched” is a genus characteristic.

slender sowthistle
Sonchus tenerrimus

• annual
• stem generally much-branched
• stem slender
• leaves deeply lobed, lobes toothed and often with smaller 2nd-order lobes
• involucre 10–12 mm
• petal ± ⅓ > corolla tube
• fruit only slightly flattened, 1–3 ribbed per face, ribs roughened
• Alum Rock [only one ID]

perennial sow thistle
Sonchus arvensis

• perennial
• stem distally branched
• basal leaves 5–15 cm, entire to deeply lobed, short-petioled
• cauline leaves coarsely lobed and toothed
• proximal clasping lobes of cauline leaves curled
• peduncles and phyllaries generally sessile-glandular, rarely tomentose
• involucre 14–18 mm
• petal ± = corolla tube
• fruit ± compressed , 3–4-angled, 2-ribbed between angles
• very rare

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2 observed taxons / 2 unobserved taxons / 1 key

Chris’s observations: 18 (6 are research grade)

Locations:

• Coyote Valley OSP: 2
• Russian Ridge OSP: 2
• Big Basin SP
• Butano SP
• Calero CP
• Coal Creek OSP
• DeLaveaga Park, Santa Cruz
• Edgewood Park & Natural Preserve
• Fremont Older OSP
• Joseph D. Grant CP
• Kauai, HI
• Purisima Creek Redwoods OSP
• San Pedro Valley CP
• Santa Teresa CP
• Sweeney Ridge National Recreation Area
• Waterdog Lake & Open Space

Months:

• Mar.: 4
• Apr.: 3
• May: 5
• Jun.: 2
• Jul.: 2
• Aug.: 1
• Sep.: 1

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Taxon info: iNaturalist – Calflora – Jepson eFlora – FNA

Bay Area species: iNaturalist – Calflora