Hemizonia congesta
Hemizonia
Cleveland's tarweed, hayfield tarweed
hayfield tarweed, tarweed
± erect.
blades 50–175+ × 2–8(–12+) mm.
mostly cauline;
proximal opposite (forming winter–spring rosettes, sometimes present at flowering), mostly alternate;
sessile;
blades narrowly elliptic to linear or lance-linear, margins serrulate or entire, faces puberulent, hispidulous, hirsute, strigose, sericeous, or villous (distal leaves sometimes stipitate-glandular as well).
hemispheric to ± urceolate or globose, 3.5–12 × 3–8+ mm.
hemispheric to ± urceolate or globose, 3–8+ mm diam. (usually subtended by calyculi of 5–7 bractlets in H. congesta subsp. calyculata).
flat to conic, glabrous, paleate (paleae connate, forming cells around all or most individual disc florets, scarious, ± deliquescent).
5–14, pistillate, fertile;
corollas white or yellow (often purple-veined abaxially).
5–12 mm.
2.5–3.5 mm.
5–60+, functionally staminate;
corollas white or yellow, tubes shorter than funnelform throats, lobes 5, deltate (anthers ± dark purple; styles glabrous proximal to branches).
5–14 in 1 series (linear to lanceolate or oblanceolate, herbaceous, each usually 1/2 enveloping a subtended ray floret proximally, abaxially pubescent to hirsute or villous, and stipitate-glandular).
radiate, borne singly or in ± paniculiform, racemiform, or spiciform arrays or in glomerules.
black, 2–3.5 mm.
0;
pappi 0.
± obcompressed, abaxially gibbous, basal attachments oblique, apices sometimes beaked, beaks inconspicuous, straight, diameters greater than lengths, faces glabrous;
pappi 0.
bracts: pit-glands, tack-glands, and/or spines 0.
= 14.
Hemizonia congesta
Hemizonia
Subspecies 6 (6 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Species 1.
Hemizonia as often circumscribed (to include Centromadia and Deinandra) is polyphyletic; molecular phylogenetic studies have indicated that Centromadia and Deinandra are more closely related to Calycadenia, Holocarpha, and Osmadenia than to Hemizonia in the strict sense, which is most closely related to Blepharizonia, also with 2n = 28 (S. Carlquist et al. 2003). Crosses between taxa of Hemizonia have yielded hybrids of minimal to full fertility; natural hybrids also have been documented (J. Clausen 1951). All taxa in Hemizonia are self-incompatible. The name H. congesta subsp. congesta has been sometimes misapplied to plants treated here as H. congesta subsp. lutescens; the type of H. congesta corresponds to plants that have been called H. leucocephala, a synonym of H. congesta subsp. congesta (B. G. Baldwin et al. 2001).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Heads in spiciform-racemiform to spiciform-paniculiform arrays (heads ± sessile); ray laminae white, abaxially purple-veined | → 2 |
1. Heads in racemiform or paniculiform arrays or in glomerules; ray laminae white or yellow, abaxially purple-veined or not | → 3 |
2. Peduncular bracts not or barely surpassing phyllaries; calyculi 0; phyllaries 3–7 mm, apices usually shorter than bodies; cypsela widths 0.6–0.75 times lengths | subsp. clevelandii |
2. Peduncular bracts (and calyculi) often notably surpassing phyllaries; calyculi usually of 5–7, sometimes 0, bractlets; phyllaries 6–12 mm, apices usually longer than bodies; cypsela widths 0.5–0.6 times lengths | subsp. calyculata |
3. Leaves usually puberulent and eglandular throughout, rarely the distal villous and glandular; heads in paniculiform arrays; ray laminae white, not purple-veined | subsp. tracyi |
3. Leaves pubescent, sericeous, or villous, all or the distal glandular; heads in paniculiform arrays or in glomerules; ray laminae white or yellow, abaxially purple-veined | → 4 |
4. Leaves ± villous (the distal with hairs at margins often longer); some or all heads usually in glomerules, sometimes in corymbiform or paniculiform arrays; phyllaries 6–10 mm, apices usually longer than bodies; ray laminae white | subsp. congesta |
4. Leaves pubescent, villous, or sericeous (the distal with hairs at margins not notably longer); heads in paniculiform arrays; phyllaries 3–7(–8) mm, apices usually shorter than bodies; ray laminae white or yellow | → 5 |
5. Ray laminae white | subsp. luzulifolia |
5. Ray laminae yellow | subsp. lutescens |
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
