Heterotheca marginata

Semple

Rev. Heterotheca Pyllotheca, 83, fig. 20. 1996.

Treatment appears in FNA Volume 20. Treatment on page 245. Mentioned on page 231, 233, 244.

Perennials, 38–80 cm, herbage abundantly long-hirsute; taprooted. Stems 1–40, ascending to erect (sometimes reddish-brown proximally, brittle), sometimes arching, hispido-scabrous (axillary leaf fascicles often present). Leaves: cauline stiff; proximal petiolate, blades oblanceolate, (180–) 240–550 × 4–7 (–9) mm, bases convex-cuneate, margins entire, strigoso-ciliate, with many long-hispido-strigose cilia all along, apices acute, mucronate, faces sparsely to moderately, coarsely hispido-scabrous, sparsely stipitate-glandular; distal sessile, blades oblanceolate, 14–31 × 3.3–5.2 mm, reduced distally, apices acute. Heads 8–50 (–78), in open paniculiform arrays. Peduncles 12–29 mm, moderately to densely hispido-strigose, sparsely stipitate-glandular; bracts 0–3, linear-oblanceolate, usually greatly reduced, rarely leaflike and linear-oblanceolate, sparsely to moderately hispido-scabrous, sparsely stipitate-glandular. Involucres campanulate, 6.5–9 (–10) mm. Phyllaries in 4–5 series, narrowly triangular-lanceolate, unequal (outer lengths 1/5–1/4 inner), scarious, faces moderately strigose (larger hairs to 1 mm), eglandular to sparsely stipitate-glandular. Ray-florets 10–15; laminae 9–14.5 × 1-2.5 mm. Disc-florets (25–) 31–46 (–50); corollas barely ampliate, 4.5–7.5 mm, tubes and throats glabrate, lobes 0.4–0.9 mm, glabrous or glabrate (hairs 0.1–0.2–0.3 mm). Cypselae monomorphic, obconic, compressed, 1.5–3.2 mm, ribs 8–10 (sometimes brownish), faces moderately strigose; pappi off-white, outer of linear scales 0.5–1 mm, inner of 35–45 bristle 4.6–7.4 mm, longest acute to weakly clavate. 2n = 18, 36.


Phenology: Flowering (Feb–)Oct(–Nov).
Habitat: Gravelly soils and crevices in sandstone outcrops, roadside margins and banks, dry hillsides, desert grassland hillsides around streams, chaparral transition areas
Elevation: 600–900 m

Discussion

Of conservation concern.

Heterotheca marginata grows in the Superstition and Pinal mountains. It is characterized by its numerous, long, hispido-strigose hairs along the entire margins of its distal leaves and peduncle bracts. The hairs give the plants a light gray-green appearance from a distance. The leaves are stiff, unlike other taxa in the section. It is similar to H. fulcrata var. arizonica, which is more glandular and typically has narrowly ovate to lanceolate bracts subtending smaller heads, and H. fulcrata var. senilis, which can be similar in indument but typically has more ovate leaves and heads subtended by narrowly ovate to lanceolate bracts.

Selected References

None.

Lower Taxa

None.

"[" 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 marginata"
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
paniculiform +  and open +
indeterminate +  and determinate +
John C. Semple +
Semple +
convex-cuneate +
compound +  and simple +
18 cm180 mm <br />0.18 m <br /> (24 cm240 mm <br />0.24 m <br />) +
0.7 cm7 mm <br />0.007 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
1.4 cm14 mm <br />0.014 m <br /> (3.1 cm31 mm <br />0.031 m <br />) +
oblanceolate;oblanceolate +
reduced +
3.3mm;5.2mm +
rugulose +  and muricate +
stipitate-glandular +
linear-oblanceolate +
reduced +
barbellulate +  and barbellate +
0.46 cm4.6 mm <br />0.0046 m <br /> (0.74 cm7.4 mm <br />0.0074 m <br />) +
rhizomatous +  and taprooted +
long-hispido-strigose +
not 2-lipped +  and actinomorphic +
ampliate +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.75 cm7.5 mm <br />0.0075 m <br />) +
compressed +  and obconic +
fertile +  and bisexual +
600–900 m +
strigose +  and stipitate-glandular +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Gravelly soils and crevices in sandstone outcrops, roadside margins and banks, dry hillsides, desert grassland hillsides around streams, chaparral transition areas +
paniculiform +
in corymbiform arrays +  and singly +
indeterminate +
heterogamous +  and homogamous +
long-hirsute +
each +  and sessile +
acute +  and weakly clavate +
tan;rusty brown +
attenuate +  and clavate +
0.9 cm9 mm <br />0.009 m <br /> (1 cm10 mm <br />0.01 m <br />) +
campanulate +
0.65 cm6.5 mm <br />0.0065 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
9mm;14.5mm +
1mm;2.5mm +
sessile +  and petiolate +
cauline +  and basal +
erect;spreading +
glabrate +  and glabrous +
lanceolate +, triangular +  and deltate +
stipitate-glandular +  and strigose +
2-carpellate +
in 3 +  and 4 series +
stipitate-glandular +  and hispido-strigose +
1.2 cm12 mm <br />0.012 m <br /> (2.9 cm29 mm <br />0.029 m <br />) +
Flowering (Feb–)Oct(–Nov). +
triangular-lanceolate +
ovate-oblanceolate +
Rev. Heterotheca Pyllotheca, +
bearing subulate enations +, hairy +  and bristly +
subulate;convex +
8 +  and 10 +
3 +  and 40 +
linear +  and linear-lanceolate or triangular +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
exalbuminous +
arching +, ascending +  and erect +
1 +  and 40 +
appendaged +  and truncate +
papillate +  and smooth +
Ammodia +, Chrysopsis subg. Ammodia +  and Heterotheca sect. Ammodia +
Heterotheca marginata +
Heterotheca +
species +
60 cm600 mm <br />0.6 m <br /> (200 cm2,000 mm <br />2 m <br />) +
38 cm380 mm <br />0.38 m <br /> (80 cm800 mm <br />0.8 m <br />) +
tree +, shrub +  and subshrub +