Heterotheca sessiliflora

(Nuttall) Shinners

Field & Lab. 19: 71. 1951.

Common names: Sessileflower goldenaster
Illustrated
Basionym: Chrysopsis sessiliflora Nuttall Trans. Amer. Philos. Soc., n. s. 7: 317. 1840
Synonyms: Chrysopsis villosa var. sessiliflora (Nuttall) A. Gray
Treatment appears in FNA Volume 20. Treatment on page 237. Mentioned on page 231, 232, 238, 249.

Perennials, (10–) 20–70 (–110) cm; taprooted. Stems 1–40+, decumbent to ascending or erect (sometimes ± brittle, sometimes reddish-brown), moderately to densely hispido-strigose (long-spreading hairs often broken off), sometimes moderately hairy and densely stipitate-glandular distally (axillary leaf fascicles sometimes present). Leaves: margins flat to strongly undulate; basal and proximal usually withering by flowering; proximal cauline subsessile, blades oblanceolate, (8–) 15–40 (–60) × (2.4–) 4–8 (–11) mm, bases cuneate, margins entire, strigoso-ciliate (proximal hairs longer, spreading), apices acute, faces moderately to densely hispido-strigose; distal sessile, blades usually narrowly to broadly lanceolate, sometimes oblanceolate, 6.5–40 × 1.5–8 mm, usually reduced distally, bases rounded, faces sparsely to densely hispido-strigose or short-strigose (5–245 hairs/mm2), sparsely to densely glandular (0–50 glands/mm2). Heads (1–) 17–36 (–126) in corymbiform or paniculiform arrays, branches ascending. Peduncles 2–100 mm, densely hispid, strigose, or glandular; bracts 2–5+, proximal lanceolate, leaflike, distal reduced, phyllary-like, (2–) 2.5–8.5 (–13) × (0.3–) 0.5–1.8 (–4) mm, sometimes a few, large, leafy bracts proximal to heads. Involucres cylindric, turbinate, or campanulate (campanulate upon drying), (6–) 7.5–11 (–15) mm. Phyllaries in 4–6 series, mid narrowly triangular, unequal (outer lengths 1/5–1/4 inner), margins hyaline, fimbriate-ciliate apically, faces very sparsely to moderately strigose, very sparsely to moderately stipitate-glandular. Ray-florets (4–) 7–15 (–24); laminae (3.5–) 4.5–10.5 (–18.5) × (0.7–) 1–1.7 (–2.4) mm. Disc-florets (9–) 20–50 (–81); corollas ± ampliate, (4–) 5.5–7 (–9.5) mm, glabrous to glabrate, lobes 0.4–1 mm, sparsely pilose (hairs 0.1–1 mm, osteolate-celled ones often fragile). Cypselae monomorphic, obconic, compressed, (1.3–) 2–3 (–4.5) mm, ribs 6–10, faces sparsely to moderately strigose; pappi off-white, outer of linear scales 0.25–0.5 mm, inner of 25–45 bristles 5–8 (–10) mm, longest attenuate to weakly clavate. 2n = 18, 36.

Discussion

Subspecies 4 (4 in the flora).

Except for Heterotheca monarchensis, H. sessiliflora is the only species in the section with long (more than 0.25 mm), fragile, osteolate-celled hairs on the corolla lobes, and it is the only species native to the central and southern coastal ranges and valleys of California. The species is divided into four subspecies and five varieties differentiated on the basis of indument features, degree of waviness of the leaf margins, and to a lesser extent, stem height and leaf shape. The treatment here is based on J. C. Semple (1996), which includes a key to and descriptions, illustrations, and distribution maps of the varieties.

Selected References

None.

Key

1 Distal leaf margins distinctly undulate; disc corolla lobe hairs 0.1–1 mm > 2
1 Distal leaf margins weakly undulate to flat; disc corolla lobe hairs 0.2–2.5 mm > 3
2 Distal leaves green, not stiff, usually densely glandular in arrays; heads often subtended by 1–3 large, leaflike bracts equaling or surpassing them, peduncle bracts sometimes phyllary-like distally; coast, dunes of south coastal ranges, 0–100 m, s California, nw Baja California (Mexico) Heterotheca sessiliflora subsp. sessiliflora
2 Distal leaves whitish, stiff; heads not subtended by leaflike bracts surpassing them, bracts reduced distally; (150–)300–1800(–2200) m, Ventura e to e San Bernadino Mountains, Mt. Palomar Heterotheca sessiliflora subsp. fastigiata
3 Proximal stems hispid; distal leaves elliptic to lanceolate, reduced distally (in tall plants), margins sometimes somewhat undulate, faces strigoso-hispid; inland hills and valleys, c California Heterotheca sessiliflora subsp. echioides
3 Proximal stems sparsely hispido-strigose; distal leaves oblanceolate, margins flat, faces long-strigose, little reduced distally; dunes, headlands, Mendocino to Santa Cruz (rarely to s of Monterey), San Francisco Bay area at 10–150 m Heterotheca sessiliflora subsp. bolanderi

"[" is not declared as a valid unit of measurement for this property."]" is not declared as a valid unit of measurement for this property.

... more about "Heterotheca sessiliflora"
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
paniculiform +  and corymbiform +
indeterminate +  and determinate +
John C. Semple +
(Nuttall) Shinners +
rounded +  and cuneate +
Chrysopsis sessiliflora +
compound +  and simple +
4 cm40 mm <br />0.04 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.8 cm8 mm <br />0.008 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
0.65 cm6.5 mm <br />0.0065 m <br /> (4 cm40 mm <br />0.04 m <br />) +
oblanceolate;lanceolate;oblanceolate +
reduced +
1.5mm;8mm +
rugulose +  and muricate +
leafy +  and phyllary-like +
0.85 cm8.5 mm <br />0.0085 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.85 cm8.5 mm <br />0.0085 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
barbellulate +  and barbellate +
0.8 cm8 mm <br />0.008 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
rhizomatous +  and taprooted +
Sessileflower goldenaster +
not 2-lipped +  and actinomorphic +
0.7 cm7 mm <br />0.007 m <br /> (0.95 cm9.5 mm <br />0.0095 m <br />) +
glabrous +  and glabrate +
ampliate +
0.55 cm5.5 mm <br />0.0055 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
compressed +  and obconic +
fertile +  and bisexual +
Calif. +  and nw Mexico +
strigose +, stipitate-glandular +, short-strigose +  and sparsely densely glandular +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
paniculiform +
in corymbiform arrays +  and singly +
indeterminate +
heterogamous +  and homogamous +
lanceolate +
reduced +
each +  and sessile +
attenuate +  and weakly clavate +
tan;rusty brown +
attenuate +  and clavate +
1.1 cm11 mm <br />0.011 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
campanulate;turbinate;campanulate;turbinate;cylindric +
0.75 cm7.5 mm <br />0.0075 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
1.05 cm10.5 mm <br />0.0105 m <br /> (1.85 cm18.5 mm <br />0.0185 m <br />) +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.24 cm2.4 mm <br />0.0024 m <br />) +
4.5mm;10.5mm +
1mm;1.7mm +
sessile +  and petiolate +
proximal +  and basal +
erect;spreading +
lanceolate +, triangular +  and deltate +
fimbriate-ciliate +  and strigoso-ciliate +
stipitate-glandular +  and strigose +
flat +  and strongly undulate +
2-carpellate +
in 3 +  and 4 series +
glandular +, strigose +  and hispid +
0.2 cm2 mm <br />0.002 m <br /> (10 cm100 mm <br />0.1 m <br />) +
lanceolate +  and linear-lanceolate +
ovate-oblanceolate +
Field & Lab. +
bearing subulate enations +, hairy +  and bristly +
subulate;convex +
6 +  and 10 +
3 +  and 40 +
linear +  and linear-lanceolate or triangular +
0.025 cm0.25 mm <br />2.5e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
exalbuminous +
Illustrated +
decumbent +  and ascending or erect +
1 +  and 40 +
appendaged +  and truncate +
papillate +  and smooth +
Chrysopsis villosa var. sessiliflora +
Heterotheca sessiliflora +
Heterotheca +
species +
70 cm700 mm <br />0.7 m <br /> (110 cm1,100 mm <br />1.1 m <br />) +
20 cm200 mm <br />0.2 m <br /> (70 cm700 mm <br />0.7 m <br />) +
tree +, shrub +  and subshrub +