Flora of North America species comparison

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Holocarpha obconica

San Joaquin tarweed
Habit Plants 10–80(–120) cm; stems ± resinous distally (not notably stipitate-glandular).
Involucres

± obconic to ± globose.
Ray florets

4–9.
Disc florets

11–21;

anthers yellow to brownish.
Phyllaries

each bearing (0–)5–15(–20) gland-tipped processes and usually glabrous or minutely sessile- or stipitate-glandular (rarely ± hispid).
Heads

in corymbiform or paniculiform arrays.
2n

= 12.

Holocarpha obconica
Phenology Flowering Apr–Nov.
Habitat Grasslands, savannas
Elevation 10–500 m (0–1600 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Holocarpha obconica ranges from the eastern San Francisco Bay area and northwest San Joaquin Valley to the Inner South Coast Ranges and is disjunct in western foothills of the southern Sierra Nevada. Often, H. obconica occurs with or near H. heermannii or H. virgata. Crossing studies have shown that different populations of H. obconica retain high interfertility; crosses to other species of Holocarpha have failed or yielded sterile hybrids (J. Clausen 1951).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 21, p. 288.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Madiinae > Holocarpha
Sibling taxa
H. heermannii, H. macradenia, H. virgata
Synonyms Hemizonia obconica, Hemizonia vernalis, H. obconica subsp. autumnalis
Name authority (J. C. Clausen & D. D. Keck) D. D. Keck: Aliso 4: 111. (1958)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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