Crepis

Annuals, biennials, or perennials, 3–120 cm; usually taprooted, sometimes rhizomatous (roots deep or shallow, woody or fibrous, caudices often woody). Stems 1–20+, erect to decumbent, simple (sometimes scapiform) or branched, usually striate, glabrous or hairy, often densely hispid or setose (hairs often stipitate-glandular). Leaves basal (often in rosettes) and cauline; petiolate (at least basal, petioles ± winged); basal blades mostly elliptic, ovate, or lanceolate to linear, or spatulate to oblanceolate, often lyrate or runcinate, margins entire, dentate, serrate, toothed, or pinnately lobed, lobes sometimes toothed; cauline usually present, lobed or entire, usually reduced in size and lobing distally. Heads (erect) usually in cymiform, corymbiform, or paniculiform arrays, sometimes borne singly. Peduncles not inflated distally, not bracteate. Calyculi of 5–12, reduced, subulate to lanceolate or deltate bractlets in ± 1 series, mostly unequal, glabrous, tomentulose, or setose. Involucres cylindric to campanulate (sometimes becoming turbinate in fruit), 4–15 mm diam. Phyllaries 5–18 in 1–2 series, lanceolate, equal or subequal, (bases becoming thickened and keeled, keels sometimes pronounced in fruit) margins green to yellowish, often scarious, apices acute to acuminate, abaxial faces glabrous, tomentose, or setose, sometimes stipitate-glandular, adaxial glabrous or with appressed hairs. Receptacles flat or convex, usually pitted, glabrous or hairy, epaleate [paleate, paleae narrow, thin]. Florets 5–100+; corollas usually yellow or orange, sometimes white, pink, or reddish. Cypselae monomorphic or dimorphic, yellow, brown, green, red, and/or black, subcylindric or fusiform, terete or subterete, usually curved, apices tapered or beaked, ribs 10–20, sometimes spiculate-roughened, faces glabrous or hispidulous; pappi persistent or falling, of 80–150, usually distinct, sometimes basally connate, white to tawny, coarse to fine, ± equal (or outer shorter), barbellulate bristles in 1–2 series. x = 3, 4, 5, 6, 11.

Distribution

North America, Eurasia, Africa, introduced nearly worldwide.

Discussion

Species ca. 200 (24 in the flora).

Crepis is generally recognized by the rosettes of coarse, often pinnately lobed leaves, erect heads, epaleate receptacles, calyculate involucres, yellow corollas, subcylindric or fusiform, ribbed cypselae, and pappi of barbellulate bristles. The taxonomy and evolutionary relationships of Crepis were studied by E. B. Babcock (1947) and his associates. Their work was thorough and important because of the effort to incorporate cytogenetic information in the evolutionary analysis. Extensive survey of chromosome number and karyotype indicated two major ploidy groups in Crepis, corresponding to New World and Old World species complexes. Of the 12 species of Crepis native to North America, 10 are polyploids with x = 11. The core diploid populations commonly occupy discrete ecologic zones and are thought to be entirely distinct from one another, yet they are interconnected by a continuous complex series of intergrading polyploid forms that are partly or completely apomictic (Babcock). The polyploids are of two forms, autopolyploids that are similar to the diploids, and allopolyploids that combine the characteristics of two or more diploid species. The allopolyploid forms of hybrid origin may exhibit the characteristics of multiple parental species and therefore are difficult to classify. Some of the heterogeneous apomictic populations, or groups of populations, have been grouped together and recognized as subspecies; those taxa are often difficult to identify and further study is clearly needed. Despite these difficulties, the subspecific taxa of Babcock were tentatively included in the present study. The Old World species are mostly diploid (n = 3, 4, 5, or 6). Babcock concluded that there was a progressive decrease in the chromosome numbers, from n = 6 to n = 3. Along with the decrease is a corresponding increase in chromosome asymmetry and reduction in chromosome length.

Selected References

Babcock, E. B. 1947. The genus Crepis. Pt. 1: The taxonomy, phylogeny, distribution, and evolution of Crepis. Pt. II: Systematic treatment. Univ. Calif. Publ. Bot. 21, 22.

Lower Taxa

Crepis acuminata, Crepis atribarba, Crepis bakeri, Crepis barbigera, Crepis biennis, Crepis bursifolia, Crepis capillaris, Crepis elegans, Crepis foetida, Crepis intermedia, Crepis modocensis, Crepis monticola, Crepis nana, Crepis nicaeënsis, Crepis occidentalis, Crepis pannonica, Crepis pleurocarpa, Crepis pulchra, Crepis rubra, Crepis runcinata, Crepis setosa, Crepis tectorum, Crepis vesicaria, Crepis zacintha

Key

1	Annuals or biennials (perennials; taproots usually shallow)	> 2
1	Perennials (taproots and caudices becoming woody)	> 11
2	Stems branched (dichotomously, heads sessile in axils); phyllaries lanceolate (inner becoming indurate, often enclosing and partially fused to cypselae)	Crepis zacintha
2	Stems branched (not dichotomously); phyllaries lanceolate to lance-linear (free from cypselae)	> 3
3	Cypselae not beaked (apices sometimes ± narrowed)	> 4
3	Cypselae (at least inner) beaked	> 8
4	Stems (at least proximally) hispid and stipitate-glandular (viscid)	Crepis pulchra
4	Stems glabrate, glabrescent, hispid, ± setose, tomentose, or tomentulose (not viscid)	> 5
5	Adaxial faces of phyllaries ± appressed-hairy (hairs white, shiny, 0.1–0.2+ mm)	> 6
5	Adaxial faces of phyllaries glabrous	> 7
6	Annuals; abaxial faces of phyllaries tomentose to hispidulous; cypselae reddish or purplish brown, 3–4 mm; pappi 4–5 mm	Crepis tectorum
6	Biennials; abaxial faces of phyllaries ± canescent-tomentose; cypselae yellowish or reddish brown, 4–7 mm; pappi 5–7 mm	Crepis biennis
7	Involucres 5–8 mm; phyllaries glandular-setose (setae black, in 2 rows); cypselae 1.5–2.5 mm	Crepis capillaris
7	Involucres 8–10 mm; phyllaries glabrous or glabrate; cypselae 2.5–4 mm	Crepis nicaeensis
8	Cypselae dimorphic	> 9
8	Cypselae usually monomorphic	> 10
9	Stems scapiform; heads 1–2 (borne singly); corollas pink or white	Crepis rubra
9	Stems branched; heads 3–10+; corollas mostly yellow, usually reddish purple abaxially	Crepis foetida
10	Stems coarsely setose or hispid (setae yellowish); calyculi of 10–14 bractlets (not reflexed); cypselae reddish brown, beaks 1–2 mm	Crepis setosa
10	Stems glabrate or hispid and/or tomentose, sometimes sparsely setose (setae black); calyculi of 5–12 bractlets (reflexed); cypselae pale brown or yellowish, beaks 2–5 mm	Crepis vesicaria
11	Plants glabrous	> 12
11	Plants usually ± hairy, sometimes glabrous	> 14
12	Stems arcuate or decumbent, scapiform; heads 2–3; cypselae beaked (beak lengths nearly 2 times bodies)	Crepis bursifolia
12	Stems ± erect or ascending, usually branched; heads 5–10(–100); cypselae seldom beaked (beaks relatively short)	> 13
13	Stems in dense clumps (plants often rhizomatous), simple or branched proximally; leaves 2–9 × 0.5–2.5 cm; involucres 8–13 mm; cypselae subcylindric to fusiform, apices sometimes tapered or narrowed, not beaked, ribs 10–13, broad, smooth; alpine habitats	Crepis nana
13	Stems in loose clumps (plants taprooted, roots vertical), branched dichotomously distally; leaves 1–4 × 0.5–1.5 cm; involucres 8–10 mm; cypselae fusiform, apices beaked (beaks 1–2 mm), ribs 10, narrow, minutely spiculate- roughened; stream banks, gravel bars	Crepis elegans
14	Leaves usually entire or weakly dentate, sometimes closely dentate, serrate, or pinnately lobed	> 15
14	Leaves usually pinnately lobed or sharply serrate	> 16
15	Stems scapiform; leaves mostly basal (rosettes), cauline leaves reduced; involucres turbinate-campanulate, 10–12 × 8–12 mm	Crepis runcinata
15	Stems branched distally; leaves mostly cauline (blades broadly oblanceolate to elliptic); involucres cylindro-campanulate, 10–15 × 6–12 mm	Crepis pannonica
16	Stems usually densely setose, stipitate-glandular (setae 1–3 mm)	Crepis monticola
16	Stems usually tomentose or tomentulose, sometimes glabrate or bristly-setose (setae or hairs to 1 mm)	> 17
17	Phyllaries tomentose to tomentulose and/or setose (setae blackish, green, or whitish); cypselae dark to olive, greenish, or reddish brown, yellowish, or blackish, weakly ribbed or striate	> 18
17	Phyllaries usually glabrous, tomentose or tomentulose, sometimes stipitate-glandular or sparsely setose (setae black); cypselae yellowish or reddish brown or dark to blackish green, distinctly ribbed	> 19
18	Plants 5–35 cm; heads 1–9; involucres 11–21 × 5–10 mm; phyllaries densely tomentose or setose	Crepis modocensis
18	Plants 20–80 cm; heads 15–20+; involucres 9–17 × 4–7 mm; phyllaries tomentulose and coarsely green-setose	Crepis barbigera
19	Phyllaries 5–8; florets 5–10(–15)	> 20
19	Phyllaries 7–18; florets 6–40	> 21
20	Heads 7–10(–30) in corymbiform arrays; phyllaries densely tomentulose near margins (strongly keeled, medians usually glabrous); cypselae reddish brown	Crepis pleurocarpa
20	Heads 30–70(–100+) in compound, corymbiform arrays; phyllaries usually glabrous, sometimes evenly tomentose (not strongly keeled); cypselae yellowish or brown	Crepis acuminata
21	Leaf lobes narrowly lanceolate or linear; cypselae dark or blackish green, apices tapered, not beaked	Crepis atribarba
21	Leaf lobes deltate or broadly lanceolate; cypselae yellowish or brownish, apices narrowed to strongly tapered	> 22
22	Plants 25–60 cm; heads (10–)20–60, in ± flat-topped, compound, corymbiform arrays; involucres narrowly cylindric, 3–5 mm diam.; florets 7–12	Crepis intermedia
22	Plants 8–40 cm; heads (1–)2–22, in corymbiform, cymiform, or paniculiform arrays; involucres cylindric, 5–15 mm diam.; florets 9–40.	> 23
23	Stems hispid, sometimes stipitate-glandular distally; leaves: faces gray-tomentose; phyllaries sometimes stipitate-glandular	Crepis occidentalis
23	Stems sparsely to densely tomentose, often stipitate-glandular proximally; leaves: faces sparsely to densely tomentose, stipitate-glandular (midribs red in fresh specimens): phyllar- ies conspicuously stipitate-glandular	Crepis bakeri