Chloracantha

G. L. Nesom

Phytologia 70: 378. 1991.

Etymology: Greek chloros, green, and akantha, thorn
Synonyms: Aster sect. Spinosi (Alexander) A. G. Jones Erigeron sect. Spinosi (Alexander) G. L. Nesom & S. D. Sundberg
Treatment appears in FNA Volume 20. Treatment on page 358. Mentioned on page 7, 16.
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 TaxonIllustrator 
FNA20 P39 Chloracantha spinosa.jpegChloracantha spinosa var. spinosa
Oreostemma alpigenum var. haydenii
Herrickia horrida
Linny Heagy
Barbara Alongi
Yevonn Wilson-Ramsey

Perennials or subshrubs (commonly appearing herbaceous), 50–150 (–250) cm, sometimes glaucous, glabrous or glabrate (forming large clones; stoutly rhizomatous). Stems erect (strict), lateral branches sharply ascending, often modified to thorns. Leaves cauline (early withering); alternate; sessile; blades 1-nerved, oblanceolate, margins entire or rarely with 1–2 pairs of small teeth. Heads radiate, borne singly in loose corymbo-paniculiform arrays. Involucres broadly turbinate to hemispheric, 4.5–7.5 × 5–6 mm. Phyllaries 20–55 in 4–5 series, (1–) 3 (–5) parallel-nerved (nerves orange-resinous; flat), oblongelliptic to lanceolate, unequal, margins hyaline (apices rounded to lanceolate), faces glabrous. Receptacles shallowly convex, smooth, epaleate. Ray-florets 20–33 in 1 (–2) series, pistillate, fertile; corollas white (coiling at maturity). Disc-florets (13–) 20–70, bisexual, fertile; corollas yellow (with orange resin ducts), tubes 2 times longer than narrowly funnelform throats, lobes 5, erect to spreading, deltate; style-branch appendages acute to deltate. Cypselae fusiform-cylindric, slightly compressed, 5 (–6) -nerved, faces glabrous; pappi persistent, of 30–60 tawny, barbellate, apically attenuate bristles in 1–2 series, usually plus shorter outer setae. x = 9.

Distribution

sw United States, w Mexico, Central America

Discussion

Species 1.

Chloracantha spinosa produces no terminal resting buds and its evergreen stems without periderm look herbaceous, but it behaves more like a subshrub in its perennial stems (alive for up to four growing seasons) with a quickly developed vascular cambium and production of axillary buds with bud scales. All or almost all of the leaves are usually shed by flowering and the colonies become masses of erect, green stems with loosely paniculiform arrays of small, terminal, white-rayed heads. Geographic variation within C. spinosa has been studied in detail by S. D. Sundberg (1991), who provided a treatment of its infraspecific taxonomy and discussions of typification problems.

... more about "Chloracantha"
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
corymbo-paniculiform +
indeterminate +  and determinate +
Scott D. Sundberg† +  and Guy L. Nesom +
G. L. Nesom +
decurrent +
oblanceolate +
rugulose +  and muricate +
not 2-lipped +  and actinomorphic +
yellow +  and white +
beaked +, 2-ribbed +  and 5-ribbed +
compressed +  and fusiform-cylindric +
fertile +  and bisexual +
fertile +  and bisexual +
sw United States +, w Mexico +  and Central America +
Greek chloros, green, and akantha, thorn +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.75 cm7.5 mm <br />0.0075 m <br />) +
broadly turbinate;hemispheric +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
erect;spreading +
deltate +
rarely +  and entire +
2-carpellate +
persistent +
parallel-nerved +
oblongelliptic +  and lanceolate +
bearing subulate enations +, hairy +  and bristly +
sundberg1991a +
exalbuminous +
acute +  and deltate +
appendaged +  and truncate +
papillate +  and smooth +
Aster sect. Spinosi +  and Erigeron sect. Spinosi +
Chloracantha +
Asteraceae tribe Astereae +
2 times longer than +
150 cm1,500 mm <br />1.5 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +
glabrate +, glabrous +  and glaucous +
50 cm500 mm <br />0.5 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +
150 cm1,500 mm <br />1.5 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +
glabrate +, glabrous +  and glaucous +