Eucephalus

Nuttall

Trans. Amer. Philos. Soc., n. s. 7: 298. 1840

Common names: Aster
Etymology: Greek eu -, good or original, and kephalotos, with a head alluding “to the elegant qualities of the calyx”—T. Nuttall 1840
Synonyms: Aster sect. Eucephalus (Nuttall) Munz & D. D. Keck ex A. G. Jones Aster subsect. Eucephalus (Nuttall) Bentham
Treatment appears in FNA Volume 20. Treatment on page 39. Mentioned on page 13, 16.
Perennials, 10–160 cm (usually cespitose, induments usually of stipitate-glandular and smooth-surfaced, curved or twisted woolly hairs, plants with caudices or short rhizomes, roots fibrous). Stems ascending or erect, simple, glabrate, puberulent, pilose, cottony, or woolly, eglandular or glandular. Leaves cauline; alternate; sessile (proximal withering by flowering; proximalmost reduced, scalelike); blades (1-nerved) ovate, elliptic, oblong, lanceolate, or linear (± uniform in size), margins entire, faces glabrate, scabrous, cottony, or woolly, eglandular or stipitate-glandular. Heads radiate or discoid, usually in open, racemiform, paniculiform, or corymbiform arrays, sometimes borne singly. Involucres turbinate-cylindric, turbinate, turbinate-obconic, or campanulate, 10–25 mm diam. Phyllaries 20–50 in 3–6 series, ± unequal (± appressed, often reddish or purplish at margins and tips), 1-nerved (keeled), ovate, lance-oblong, lanceolate, linear-oblong, or linear, chartaceous at bases, margins sometimes hyaline, especially proximally; apices acute to obtuse, green, usually puberulent, tomentose, and/or stipitate-glandular, sometimes glabrous. Receptacles ± flat, pitted, epaleate. Ray florets 0–21 (usually 5, 8, or 13), pistillate, fertile; corollas violet-purple, purple, pink, or white. Disc florets 10–35, bisexual, fertile; corollas yellow, ± ampliate, tubes shorter than funnelform throats, lobes 5, erect or reflexed, triangular; style-branch appendages lanceolate. Cypselae ± obconic, flattened, laterally 1–2-ribbed, sometimes with 1–2 additional nerves on each face, glabrous, pilose, or strigose, eglandular; pappi persistent, of 30–50 whitish to tawny, barbellate or smooth, apically clavate or more conspicuously barbellate bristles in 2(–3) series (outer usually 1 mm or less, sometimes 0, inner 5–10 mm). x = 9.

Distribution

North America.

Discussion

Species 10 (10 in the flora).

Eucephalus, a relatively well-marked western North American group, has been treated as a section of Aster or as a distinct genus. Recent molecular evidence places Eucephalus, together with the eastern North American Doellingeria, at the base of the North American clade of Astereae.

References

None.

Key

1 Ray florets usually 1–4, often 0 > 2
1 Ray florets commonly 5, 8, or 13+ > 5
2 Ray florets 0; leaves 5–9 cm, ± glabrous abaxially, glandular adaxially; plants 60–120 cm; open woods, Lane County, Oregon Eucephalus vialis
2 Ray florets usually 1–4; leaves 2–6 cm, hairy; plants 10–100 cm > 3
3 Leaves glabrous or nearly so abaxially, moderately to densely hairy adaxially Eucephalus tomentellus
3 Leaves glabrous, eglandular or sparsely glandular on both faces > 4
4 Phyllaries subequal Eucephalus breweri
4 Phyllaries strongly unequal Eucephalus glabratus
5 Stems, leaves, and phyllaries glabrous, glaucous; plants 40–160 cm; leaves linear tonarrowly lance-elliptic, 4–10 cm; rays purple Eucephalus glaucescens
5 Stems, leaves, and phyllaries pubescent or glabrate, glandular or not, not glaucous; plants 10–120(–150) cm; leaves elliptic, oblong, lance-ovate, lance-elliptic, lanceolate, linear-oblong or -lanceolate, 1.5–10 cm; rays white, pink, violet, or purple. > 6
6 Leaves 5–10 cm, elliptic to lanceolate, glabrous and eglandular, or abaxially ± glandular and/or villous; plants 50–150 cm; rays white to pink Eucephalus engelmannii
6 Leaves 1.5–7 cm, elliptic, elliptic-oblong, oblong, lance-ovate, lance-elliptic, linear-oblong or -lanceolate, glandular or not, scabrous or cottony; plants 10–80 cm; rays white or violet to purple > 7
7 Rays white; stems pilose or sparsely to moderately glandular-pubescent > 8
7 Rays violet to purple; stems scabrous (to scabrellous) or cottony and/or glandular-pubescent (especially peduncles) > 9
8 Phyllaries lance-ovate; Cascade Mountains, Oregon Eucephalus gormanii
8 Phyllaries lance-linear; Olympic Mountains, Washington Eucephalus paucicapitatus
9 Leaves moderately scabrellous (and sometimes glandular) on both faces Eucephalus elegans
9 Leaves sparsely scabrous abaxially, strongly cottony adaxially Eucephalus ledophyllus