Native California Roses

copyright Barbara Ertter, 2001
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Rosa bridgesiiCrépin ex Rydberg
"Sierra Ground Rose"

Description Distribution Discussion Horticultural Notes Nomenclature Links

open low-growing plants, often in mid-montane conifer understory leaves often blunt-tipped; flowers mostly solitary, prickles paired at nodes hips and pedicel glabrous, rarely with some stalked glands line drawing


DESCRIPTION: Openly rhizomatous dwarf shrub, generally 1--8 dm tall. Stem dark brownish; prickles few, generally paired, moderately slender, straight. Leaf 3--8(12) cm long; stipule margins with distinct glands; leaflets 2--3 per side, finely hairy and/or glandular; terminal leaflet generally 10--30 mm long, often widely obovate (elliptic), the base obtuse, the tip often truncate; leaf-margins generally double-toothed, glandular. Inflorescence 1--few-flowered; pedicels generally 5--15(20) mm long, glabrous to glandular. Flowers: body of hip in flower generally 2.5--4 mm wide, generally glabrous (rarely sparsely stalked-glandular), neck of hip generally 1.5--2 mm wide; sepals generally glandular, sepal-tip generally shorter than sepal-body, entire; petals generally 10--15(20) mm long; pistils 5--20 in number. Hip ovoid to globose, 6--10 mm wide, generally glabrous (rarely sparsely stalked-glandular), neck 1.5--4 mm wide, sepals persistent. Blooming May to August. Open forest floors, rocky areas; 900--2000 m elev.

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DISTRIBUTION OF ROSA BRIDGESII IN CALIFORNIA:
Most common in central & southern Sierra Nevada, more scattered in northern Sierra Nevada and southern Cascade Mountains, north to Jackson Co., Oregon.

Additional distributional representations available from links at entry for this species in the Jepson Interchange for On-Line Floristics

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DISCUSSION: Rosa bridgesii as used here and in The Jepson Manual (but see discussion under Nomenclature) effectively replaces R. pinetorum as used in most previous references, including Munz's A California Flora (1959). It also encompasses most references to R. spithamea in the Sierra Nevada, as well as any to R. gymnocarpa var. pubescens. The name R. pinetorum is now used only for a handful of populations occurring on and around the Monterey Peninsula, which includes the type of R. pinetorum. As previously defined by Munz, Rosa spithamea and R. pinetorum occurred in both the Coast Ranges and the Sierra Nevada, as far south in the latter as Tulare County. However, essentially all specimens from the Sierra Nevada identified as these two species (as well as many identified as Rosa californica and Rosa gymnocarpa) group together to form a relatively well-defined species that differs from either typical R. spithamea or the type of R. pinetorum. Unlike R. spithamea, the hips of the Sierra ground rose are usually glabrous (rarely sparsely glandular), the prickles occur in pairs at the nodes (one synonym is Rosa spithamea var. subinermis Engelm.), and flowers are commonly solitary. The hips of R. pinetorum are also glabrous, but the pine rose generally has more dense prickles and more flowers. (see Comparative Table)

The Sierra ground rose is most common in the understory of the lower montane forest, including the famous Sequoiadendron groves, where it forms open stands on the forest floor. The species is most distinctive at the southern end of its range, where the leaflets are widely and diagnostically blunt-tipped. Identity becomes problematic in the northern part of the range, where plants can be difficult to distinguish from non-fruiting Rosa gymnocarpa. However, the leaves of Rosa bridgesii are generally more or less finely hairy, whereas those of Rosa gymnocarpa are glabrous. One of the many synonyms of the Sierra ground rose, and in fact the earliest one published, is Rosa gymnocarpa var. pubescens S. Watson. In and around Yuba County, however, some populations (including the type of R. lesterae Eastwood) that are typical R. bridgesii in most other regards have leaflets that lack hairs, being instead dotted with glands.

In contrast to the understory habit of R. bridgesii in the central and southern Sierra Nevada, where the species is more common, at least some populations from the northern Sierra Nevada and Cascades Mountains of northern California and south Oregon occur on bare rocky ridges (see photos below). Oregon populations have been given the name R. spithamea var. solitaria L.F. Henderson, but thus far no significant morphological differences have been discerned between these plants and those from further south. The type of R. yainacensis might also represent this northern condition, though habitat is not recorded and extant populations from the type locality have not yet been found (see Nomenclature, below).

plants growing on open rocky ridge, Huckleberry Mountain, Jackson Co., Oregon note solitary flowers, paired prickles, glabrous hips

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HORTICULTURAL NOTES: The Sierra ground rose should be a charming addition to an open woodland garden, though the species does not appear to do as well in coastal areas as does R. spithamea.

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NOMENCLATURE: Unfortunately, it now turns out that the combination Rosa bridgesii was never actually used by Crépin in his 1876 treatment of North American roses, even though it was attributed to him when Rydberg later resurrected the name in 1917. By this time, however, several additional names for the Sierran Ground Rose had been published, one of which needs to be adopted in place of Rosa bridgesii, according to the International Code of Botanical Nomenclature. To make matters worse, the earliest potential candidate, Rosa yainacensis Greene, may or may not represent the same species, and field work to date in the presumed type locality of R. yainacensis (Yainax Ridge in Klamath Co., Oregon) has yet to locate populations comparable to the type. If R. yainacensis is not the same species, then one of the next two earliest available names, R. calvaria Greene and R. crenulata Greene (published in the same paper), would need to be adopted instead. Rather than risk adding yet one more superfluous name to what is already a nomenclatural jumble, I am continuing the use of Rosa bridgesii until the relationship of R. yainacensis to the Sierra Ground Rose is more fully and reliably determined.

Probable Synonyms (working list):
R. bridgesii Crépin ex Rydb., North Amer. Fl. 22: 532. 1917 [not validly published by Crépin, Bull. Soc. Bot. Belg. 15: 54. 1876]: Bridges 62 -- California (K, B)
R. calvaria Greene, Leafl. Bot. Observ. Crit. 2: 257. 1912: Greene s.n., Jun 1889 -- Calaveras Big Trees, Calaveras Co., CA (HT: NDG11192!)
R. crenulata Greene, Leafl. Bot. Observ. Crit. 2: 255. 1912: Hall & Chandler 171-- Pine Ridge, Fresno Co., CA (HT: US!; IS: MO! NY! UC!)
R. dudleyi Rydb., Bull. Torrey Bot. Club 44: 73. 1917: Dudley 3388-- Converse Basin, Fresno Co., CA (HT: DS!)
R. gymnocarpa var. pubescens S. Watson in W.H. Brewer & Watson, Bot. Calif. 1: 187. 1876: Gray-- Wawona, CA (HT: GH)
R. lesterae Eastwood, Leafl. W. Bot. 3: 262. 1943: Rowntree s.n.-- between Dobbins and Camptonville, Yuba Co., CA (HT: CAS 290633!) = bridgesii with glabrous leaflets
R. spithamea var. solitaria L.F.Hend., Rhodora 33: 204. 1931: Henderson 13238-- Diamond Lake to North Umpqua River, Douglas Co., OR (HT: ORE)
R. spithamea var. subinermis Engelm., Bot. Gaz. 6: 236. 1881: Engelmann s.n.-- Fresno Big Trees, CA (HT: MO1798985!)
!R. yainacensis Greene, Pittonia 5: 109. 1903: Austin s.n.-- Yainax Indian Reservation, s OR (HT: NDG; fragment at NY!)

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LINKS:

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