Arnoglossum

Perennials, 30–300 cm. Stems usually 1, erect (unbranched proximal to heads). Leaves basal and cauline; alternate; petiolate or sessile; blades palmately nerved, mostly cordate, deltate, elliptic, hastate, ovate, or reniform, sometimes lanceolate or lance-linear, margins entire, ± dentate to denticulate, sinuate, or lobed, faces usually glabrous. Heads discoid, in corymbiform arrays. Calyculi 0. Involucres cylindric to turbinate, 2.5–5 mm diam. Phyllaries persistent, 5 in 1–2 series, erect (spreading in fruit), distinct, ovate or oblong to linear (midveins sometimes winged), ± equal, margins scarious (hyaline). Receptacles flat or convex (usually with central cusp 0.5–2 mm), foveolate, epaleate. Ray florets 0. Disc florets 5, bisexual, fertile; corollas usually creamy or greenish white, rarely purplish distally, tubes longer than to equaling campanulate to funnelform throats, lobes 5, spreading or recurved, lanceolate; style branches: stigmatic areas continuous, apices truncate or truncate-penicillate (appendages essentially 0). Cypselae clavate, cylindric, ellipsoid, or ± fusiform, (4–)10–15-ribbed or -nerved, glabrous (resinous); pappi persistent, fragile, or readily falling, of 100–120+, white, smooth or barbellate bristles. x = 28.

Distribution

e North America.

Discussion

Species 8 (8 in the flora).

The name Cacalia Linnaeus has been misapplied to Arnoglossum.

Selected References

Kral, R. and R. K. Godfrey. 1958. Synopsis of the Florida species of Cacalia. Quart. J. Florida Acad. Sci. 21: 193–206.

Pippen, R. W. 1978. Cacalia. In: N. L. Britton et al., eds. 1905+. North American Flora.... 47+ vols. New York. Ser. 2, part 10, pp. 151–159.

Robinson, H. 1974b. Studies in the Senecioneae (Asteraceae). VI. The genus Arnoglossum. Phytologia 28: 294–295.

Lower Taxa

Arnoglossum album, Arnoglossum atriplicifolium, Arnoglossum diversifolium, Arnoglossum floridanum, Arnoglossum ovatum, Arnoglossum plantagineum, Arnoglossum reniforme, Arnoglossum sulcatum

Key

1	Phyllary midveins not winged (leaves ± membranous)	> 2
1	Phyllary midveins winged (leaves firm)	> 4
2	Basal leaves (and proximal cauline): blades ovate to narrowly lanceolate or lance-linear, margins usually entire	Arnoglossum ovatum
2	Basal leaves (and proximal cauline): blades ovate, ovate-cordate, or reniform, margins lobed or dentate	> 3
3	Stems smooth to weakly striate (stems and abaxial leaf faces glaucous)	Arnoglossum atriplicifolium
3	Stems ridged to angulate (stems and abaxial leaf faces not glaucous)	Arnoglossum reniforme
4	Basal leaves: blades ovate to cordate-ovate (bases truncate), margins denticulate; proximal cauline leaves deltate-hastate, margins dentate	Arnoglossum diversifolium
4	Basal leaves: blades elliptic, ovate, ovate-oblong, or lance-oblong, margins crenate, crenulate, denticulate, entire, serrulate-denticulate, or sinuate; proximal cauline leaves ovate or elliptic, margins crenulate, denticulate, entire, serrate, or sinuate	> 5
5	Phyllary wings (erose) highest at bases (lateral veins of basal leaves appressed to midveins 2–4 cm, then spreading)	Arnoglossum album
5	Phyllary wings (entire or sinuate) ± uniform or highest at apices (lateral veins of leaves spreading from bases)	> 6
6	Involucres 12–15 mm; corollas (9–)11–12 mm; cauline leaves: margins crenulate	Arnoglossum floridanum
6	Involucres 8–14 mm; corollas 7–11.5 mm; cauline leaves: margins crenulate, denticulate, entire, serrulate, or sinuate	> 7
7	Involucres (9.5–)10–12(–14) mm; corollas 8–10(–11.5) mm (mid-stem leaves petiolate, bases rounded)	Arnoglossum plantagineum
7	Involucres (8–)9.5–10(–12) mm; corollas 7–8(–9.5) mm (mid-stem leaves sessile, bases broadly cuneate)	Arnoglossum sulcatum