Perityle

Bentham

Bot. Voy. Sulphur, 23, plate 15. 1844.

Common names: Rock daisy
Etymology: Greek peri, around, and tyle, a callus, alluding to calloused cypselae margins
Treatment appears in FNA Volume 21. Treatment on page 317. Mentioned on page 333, 334.

Annuals, perennials, subshrubs, or shrubs, 2–45(–75) cm (glabrous or hairy, often gland-dotted). Stems erect to pendent. Leaves mostly cauline; often proximally opposite, distally alternate; petiolate or sessile; blades usually 3-lobed, ultimate margins entire, toothed, or lobed. Heads radiate or discoid, borne singly or in corymbiform arrays. Involucres campanulate, cylindric, funnelform, or hemispheric, 3–15 mm diam. Phyllaries persistent, 5–28 in (1–)2(–3) series (distinct, linear to ovate, equal or subequal, flat or keeled, glabrous or hairy, apices obtuse, acute, or attenuate). Receptacles flat or convex, pitted, epaleate. Ray florets 0, or (1–)3–18, pistillate, fertile; corollas cream, yellow, or white (showy or rudimentary). Disc florets 5–200, bisexual, fertile; corollas cream, yellow, or white, tubes shorter than or nearly equal to cylindric, funnelform, or campanulate throats, lobes 4, ± deltate (acute; stamens 4; style branches flattened, linear, usually tapering to fine, minutely hairy tips). Cypselae (black) flattened to subcylindric, linear to oblanceolate or obovate (margins ± calloused and glabrous, hairy, or ciliate, faces usually hairy, sometimes glabrous); pappi 0, or persistent or falling, of 1–35 bristles plus callous crowns or hyaline scales. x = 17, 19.

Distribution

United States, Mexico, South America.

Discussion

Species 66 (35 in the flora).

Most species of Perityle are rock-dwelling subshrubs exhibiting geographic speciation; most are found in the eroded mountain and basin region of the southwestern United States.

Selected References

None.

Key

1 Pappi (disc florets) usually each of 8–35 unequal, antrorsely barbellulate bristles 0.5–3.5 mm (in P. vitreomontana all but 2–3 may be reduced to vestigial nubs); New Mexico, Texas Perityle sect. Pappothrix
1 Pappi (disc florets) 0, or of 1–2(–6) bristles, sometimes plus callous crowns or scales; Arizona, California, Nevada, New Mexico, Texas, and Utah > 2
2 Pappi (disc florets) 0, or of 1–2(–3) unequal to subequal, ± barbellate bristles 0.5–4(–6) mm plus hyaline, laciniate scales; margins of cypselae usually densely ciliate Perityle sect. Perityle
2 Pappi (disc florets) 0, or of 1–2(–6) equal or subequal, antrorsely barbellulate or subplumose bristles 0.5–4.6 mm plus callous crowns or hyaline scales; margins of cypselae usually sparsely short-hairy Perityle sect. Laphamia
... more about "Perityle"
Sharon C. Yarborough +  and A. Michael Powell +
Bentham +
Rock daisy +
United States +, Mexico +  and South America. +
Greek peri, around, and tyle, a callus, alluding to calloused cypselae margins +
Bot. Voy. Sulphur, +
Undefined (tribe Undefined) subtribe Amauriinae +
Perityle +
Asteraceae (tribe Heliantheae) subtribe Peritylinae +