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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

JENSIA TARWEED, TARPLANT

Bruce G. Baldwin


Annual 5–60 cm. Stem: erect. Leaf: basal and cauline, proximal opposite, often crowded, distal alternate, sessile, spoon-shaped to linear, entire or toothed, coarse-hairy to strigose, distal sometimes also stalked-glandular. Inflorescence: heads radiate, in ± umbel-like clusters; involucre 3–5 mm diam, ± obconic or urn-shaped to spheric; phyllaries 2–12 in 1 series, lanceolate (often long-tapered), each generally wholly enveloping a ray ovary, falling with fruit, coarse-hairy, hair tips ± hooked; receptacle flat to convex, glabrous or minutely bristly; paleae in 1 series between ray and disk flowers, fused, phyllary-like to ± scarious, deciduous. Ray flower: 2–12; corolla yellow, ray sometimes purple-veined abaxially. Disk flower: 1–65, staminate; corolla yellow, tube < throat, lobes deltate; anthers ± dark purple, tips ovate-deltate; style glabrous proximal to branches, tips narrowly lance-awl-shaped, densely hairy. Fruit: ray fruit compressed, club-shaped, arched, glabrous, tip beaked, pappus crown-like, scales 0.1–1 mm; disk pappus of 5–7 scales, 2.5–3 mm, white or purple-tipped, awl-shaped, wavy, minutely ciliate.
2 species: California. (Jens C. Clausen, California botanist, 1891–1969) [Baldwin & Strother 2006 FNANM 21:301–302]
Unabridged disk flower: anther bases ± cordate.
Unabridged references: [Carlquist 2003 Tarweeds and silverswords: evolution of the Madiinae (Asteraceae)]

Key to Jensia

1. Involucre urn-shaped or spheric; ray flowers 5–12, ray 4–10 mm; disk flowers 16–65; plants 6–60 cm ..... J. rammii

1' Involucre broadly obconic; ray flowers 2–8, ray 0.5–3 mm; disk flowers 1–7; plants 5–15(25) cm ..... J. yosemitana

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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