Stephanomeria paniculata |
Stephanomeria elata |
|
---|---|---|
stiff-branch stephanomeria, stiff-branch wirelettuce, tuft wirelettuce |
Nuttall's wirelettuce, Santa Barbara stephanomeria, Santa Barbara wirelettuce |
|
Habit | Annuals, 0–100 cm. | Annuals, 50–150 cm. |
Stems | single, branched (branches nearly at right angles, stiff), glabrous. |
single, branches ascending or spreading, glabrous, puberulent, or glandular-pubescent. |
Leaves | withered at flowering; basal blades oblanceolate, 6–10 cm, margins entire or toothed (teeth minute, faces glabrous); cauline much reduced, bractlike. |
withered at flowering (glabrous or puberulent); basal blades linear to oblanceolate, runcinate, 3–10 cm, margins pinnately lobed; cauline much reduced, bractlike. |
Peduncles | 2–10 mm. |
3–7 mm. |
Involucres | 6–9 mm. |
5–7 mm (glabrous, puberulent, or stipitate-glandular). |
Florets | 5. |
9–15. |
Calyculi | of appressed bractlets. |
of usually reflexed, rarely appressed bractlets. |
Heads | borne singly along branches or in paniculiform arrays. |
borne singly or clustered along branches. |
Cypselae | light to dark tan, 3.8–4.2 mm, faces slightly bumpy to tuberculate, (grooved); pappi of 15–18 tan bristles (connate in groups of 2–4, bases persistent), plumose to tops of bases. |
light tan to dark brown, 2.8–4.5 mm, faces smooth to strongly tuberculate, grooved; pappi of 17–22 white or tan bristles (falling or widened bases persistent, bases connate in groups of 2–4, distal portions breaking off), wholly plumose. |
2n | = 16. |
= 32. |
Stephanomeria paniculata |
Stephanomeria elata |
|
Phenology | Flowering Jun–Sep. | Flowering Jul–Oct. |
Habitat | Open, sandy or volcanic soils, plains and foothills, often growing as weed along roads | Chaparral openings, grassy meadows, forest openings, roadsides, often growing as weed |
Elevation | 200–1400 m (700–4600 ft) | 100–1400 m (300–4600 ft) |
Distribution |
CA; ID; OR; WA
|
CA; OR
|
Discussion | Stephanomeria elata grows in the coastal foothills and mountains, the western slopes of Sierra Nevada, and southwest Oregon. All the tetraploid populations of annual stephanomerias are placed into Stephanomeria elata. The plants are self-compatible and are highly self-pollinating. Stephanomeria elata is an allotetraploid species that arose following hybridization between S. exigua and S. virgata (L. D. Gottlieb 1972). Substantial interpopulation morphologic variability occurs in the length, width, and color of ligules, number of florets, and degree of reflexing of bractlets of the calyculi. Two groups of populations can be distinguished. One group has large cypselae, averaging 3.9–4.5 mm, the bristle bases are widened, and about 30% of the pollen grains have four pores. The second group has smaller cypselae, averaging 2.8–3.3 mm, the bristle bases are not widened, and less than 10% of the pollen grains have four pores. The former group of populations is generally found from southwestern Oregon south to Monterey County in the Coast Ranges of California and on the western slopes of the Sierra Nevada to Fresno County. The latter group is distributed near the coast from Marin County to Santa Barbara County, California. The two groups overlap in Santa Cruz, Santa Clara, and Monterey counties; the distinctions are less evident there. Stephanomeria elata and its parents S. exigua and S. virgata form a polyploid complex that perplexed taxonomists for many years. Once the morphologic distinctions between parental species were clarified (L. D. Gottlieb 1972), particularly, the presence versus absence of the longitudinal groove on each face of their cypselae that distinguishes S. exigua and S. elata from S. virgata, and the allotetraploidy of S. elata was recognized, it has become much simpler to distinguish the three species in the field. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 19, p. 356. | FNA vol. 19, p. 353. |
Parent taxa | Asteraceae > tribe Cichorieae > Stephanomeria | Asteraceae > tribe Cichorieae > Stephanomeria |
Sibling taxa | ||
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 428. (1841) | Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 20. (1848) |
Web links |
|