Muhlenbergia: A Journal of Botany, 1(4): 53-54 (Feb 22, 1904)
A. A. Heller
Rosa pinetorum

Stems slender, clustered, erect, sparingly branched, 6-8dm. high, usually densely prickly below, the prickles very slender, rather weak, straight, about 5mm. long, with scarcely dilated base, or with occasional stouter ones 1cm. long with enlarged base, these large ones principally upon young shoots: leaves glandless, somewhat coriaceous, either elliptical-ovate or almost orbicular, the larger nearly 3cm. long, over 2cm. wide, sharply serrate except at the rounded or truncate base, the lower serratures usually gland tipped; or the smaller leaves with somewhat cuneate base, deep green and glabrous above, beneath paler and somewhat pubescent, especially on the veins, of which the midvein only is prominent but not pale; rachis prickly and somewhat glandular, the glands stalked stipules entire, acute, usually glandular on the margin: flowers commonly solitary, sometimes two or three in a corymb: calyx lobes about 2cm. long, lanceolate, sometimes broadly so, the margins densely ciliate with white woolly hairs, either glandular or smooth: the slender tip commonly enlarged and foliaceous: corollas deep rose-purple, about 4cm. across, the petals somewhat notched: ovary globose, smooth and glabrous.

No. 6817, collected in sandy pine woods about Pacific Grove, Monterey county, California, June 3, 1903. This species is perhaps more related to the southern R. gratissima Greene, than it is to R. Californica.

Here is also referred a form collected in damp grassy places in the woods back of Pacific Grove, which has an irregularly crenate-serrate, more uniformly rounded leaf with prominent pale veins, the calyx lobes with larger foliaceous tips, which are somewhat serrate. It is lower in stature and more branched. Although quite a marked form, it is for the present included under R. pinetorum.

Las Pilitas Nursery sells a rose as Rosa pinetorum, describing its provenance as the Sierra Nevada. This may be Rosa bridgesii, as the morphology seems to generally match the description given by Ertter for both roses.

Leaves have 7-9 leaflets, glandular beneath, 7-8 cm long, weak prickles + glands on reverse of petiole, upper surface matte, leaflet margins singly serrate with minute hairs + glands.

The tiny blooms are 1.5in/38 mm wide, 5 whitish petals in full sun. Both pedicel and reverse of sepals are glandular. Blooms in ones and twos and not profuse. From tip of sepal to base of pedicel measures only 15/16in/24 mm. Blooming 12 June 2010 in Sonoma County.

Straight prickles on canes are usually paired and consistently paired below leaves. Two-toned when new.

See photos.