Rosa corymbulosa (Species)

Curtis's Botanical Magazine (Jul 1914) vol.140, Tab. 8566.
China.
Rosaceae. Tribe Roseae.
Rosa, Linn,; Benth. et Hook, f. Gen. Plant, vol. i. p. 625.

Rosa (§ Cinnamomeae) corymbulosa, Rolfe; species distincta, inter affines ramulis inermibus vel parce armatis, floribus parvis numerosis et corymbulosim dispositia distinguenda.

Frutex erectus vel scandens, parce ramosus, 1-2-metralis; ramuli laeves, inermes vel interdum parce aculeati, aculeis geminatis rectis patentibus gracilibus 5-6 mm. longis basi latis, demum brunnei. Folia conferta, 4-9 cm. longa, 3-5-foliolata ; rhachis puberula et sparse glandulosa, aculeis gracilibus paucis instructa; foliola subsessilia, ovato-oblonga, subacuta, crebre duplicato-serrata, subtus glauca vel cinereo-puberula, 1.5 cm. longa. 0.4-2 cm. lata; stipulae adnatae, anguste oblongae, acutae, 8-10 mm. longae, marginibus crebre glandulosis. Flores corymbulosi, numerosi, versus apices ramorum dispositi, 2-2.5 cm. diametro; pedunculi circiter 2 cm. longi, glanduloso-setolosi. Receptaculum ovoideo-oblongum, glanduloso-setulosum, 4 mm. longum. Calycis lobi ovato-oblongi, caudato-acuminati, puberuli vel subtomentosi, circiter 8 mm. longi, patentes vel reflexi. Petala late obcordata. Filamenta glabra, 2-3 mm. longa, antheris aureis. Fructus globosas, glandulosus, circiter 8 mm. longus, sepalis persistentibus coronatus. Achaenia dorso villosa, 2 mm. longa; styli villosi, in columnam 4 mm. longam cohaerentes. — R. A. Rolfe.

The distinct and striking Rose here described is perhaps most nearly allied to R. macrophylla, Lindl., but differs in being almost spineless when mature, and in having many small flowers which are borne in corymbs towards the ends of the branches. It was raised at Kew from seeds presented by Professor Sargent of the Arnold Arboretum, Jamaica Plain, Massachusetts, in the spring of 1908. These seeds had been collected in Western China in autumn 1907, under the field-number 630A, by Mr. E. H. Wilson. The plant from which the material for our plate has been obtained flowered at Kew for the first time in July 1913. At present this plant is a bush about six feet in height, and promises to be a fairly vigorous grower, thriving well in the rather strong loam that roses as a whole delight in. R.corymbulosa had previously been met with in China, for there are specimens in the herbarium at Kew collected by Mr. A. Henry near Wushan in the province of Szechuan and at Hsingshen in the province of Hupeh.

Description.— Shrub, erect or scandent, sparingly branched, 3-6 ft. high; twigs smooth, when old brown, unarmed or at times sparingly prickly, prickles geminate, straight, spreading, slender, 1/5-1/4 in. long. Leaves rather close-set, 1 1/2-3 1/2 in. long, 3-5-foliolate; rachis puberulous and sparingly glandular, with a few slender prickles; leaflets subsessile, ovate-oblong, subacute, closely duplicate-serrate, beneath glaucous or grey-puberulous, 2/3 in. long, 1/6-3/4 in. wide; stipules adnate, narrow-oblong, acute, about 1/3 in. long, their margin closely glandular. Flowers numerous, in small corymbs towards the ends of the branches, 3/4-1 in. in diameter; peduncles about 3/4 in. long glandular-setulose. Receptacle ovoid-oblong, glandular setulose, 1/6 in. long. Calyx-lobes ovate-oblong, caudate-acuminate, puberulous or almost tomentose, about 1/6 in. long, spreading or reflexed, Petals wide-obcordate. Filaments glabrous, 1/12-1/8 in. long, with anthers golden-yellow. Fruit globose, glandular, about 1/3 in. long, tipped by the persistent sepals. Achenes villous on the back, 1/12 in. long; styles villous, conjoined in a column 1/6 in. long.

Fig. 1, stipules and a proximal leaflet; 2, a flower in vertical section, the petals removed; 3 and 4, anthers; 5, an achene:—all enlarged.