Rubus haridasanii Chand. Gupta & S. S. Dash, 2016

Dash, Sudhansu Sekhar, Gupta, Chandani & Bhuyan, Lakhi Ram, 2016, A new species of Rubus L. (Rosaceae) from Arunachal Pradesh, India, Phytotaxa 289 (2), pp. 175-180 : 176-179

Rubus haridasanii Chand. Gupta & S. S. Dash , sp. nov. ( Fig. 1 & 2 )

Type:— INDIA. Arunachal Pradesh: Lower Subansiri district, Talley Valley, 1875 m, 10 June 1984, K. Haridasan 1097 (Holotype CAL!).

Rubus haridasanii is morphologically allied to R. preptanthus in having unlobed, oblong-elliptic leaves with abaxially tomentose vesture,

and corymbose raceme inflorescences, but differs in having caudate-acuminate leaves, 5- or 6-flowered inflorescences, stipitate glandular pedicels and calyx, calyx lobes with long caudate apex armed with weak needle-like prickles.

Shrub, straggling, to 4 m tall. Stem terete, woody, usually with small sharp recurved prickles, tomentose, gradually glabrous at maturity. Leaves alternate, simple; petiole slender, 1–1.5 cm long, prickly, tomentose and slightly villous when young, glabrous at maturity; stipules caducous; blade oblong-elliptic, unlobed, 3.2–9.2 × 1.2–3.3 cm, base subtruncate to truncate, margin irregularly incised to double serration, apex long acuminate-caudate, lateral veins 7–9 pairs, abaxially grey tomentose, prickly on midvein, adaxially glabrous. Inflorescences terminal corymbose racemes, 5- or 6-flowered; pedicels slender, ca. 1 cm long, densely grey tomentose or villous, stipitate glandular with needle like prickles; bracts not seen. Flowers bisexual; calyx gamopetalous, united part ca. 2 mm long, lobes 5, narrowly ovate, 12–13 × 3–4 mm, apex caudate—acuminate, simple, stipitate glandular, usually with straight but weak needle-like prickles, both adaxial and abaxial surfaces densely grey tomentose, or more along abaxially; petals 5, white, obovate, 7–8 × 4–5 mm, base narrowed, truncate, margin entire, minutely hairy, apex obtuse or rounded, outer surface hairy, inner surface glabrous; stamens> 70, in unequal series, shorter than petals, filaments 5–6 mm long, glabrous; anthers dorsifixed, distinctly 2-lobed, ca. 1 mm long, dehiscence longitudinally latrorse, sparsely villous; pistils many, apocarpous, equaling to stamens, ovary ca. 1 mm long, glabrous, superior; style 1, sub-terminal, ca. 6 mm long, glabrous; stigma thickened; torus slightly convex.

Pollen morphology:— The pollen grains are 3-colporate, prolate spheroidal, 3-lobed in polar outline ( P / E ratio

1.03), 28–30 μm toward the poles with obtuse angled ends, which are often undifferentiated, colpus widely constricted at equator, distinctly undulate along the edges; the equatorial bridge is distinct. The colpus membrane is covered with granulations, particularly along the edges. The endoaperature is smooth, indistinct and usually hidden under the rugged exine or equatorial bridge. The exine layer is thick, finely ornamented. The surface ornamentation is finely striate, rarely verrucose-perforate. The muri are arranged meridionally, narrow and predominantly anastomosing by interconnection of their distant ends, more often creating a perforated tectum. There are 2 or 3 anastomoses per 10 μm in length. The perforations are dense and uniform. ( Fig. 3 ).

Distribution:— India, Arunachal Pradesh; known only from the type locality.

Habitat and ecology:— Rubus haridasanii grows in open temperate forests between 1800 and 2700 m.

Flowering and fruiting: — May to August.

Etymology:— The species is named after Dr. K. Haridasan, former scientist at the State Forest Research Institute, Itanagar, Arunachal Pradesh, and also the collector of the type specimen.

Provisional IUCN (2012) conservation assessment:— Rubus haridasanii is known only from the type locality in Talley valley in Arunachal Pradesh, India. Although it was mentioned in the field data that it is commonly found in the region, so far, no subsequent collections from India are known, hence, its conservation status is considered Data Deficient (DD).

Notes:— Due to its shrubby habit, prickly stem, simple leaves, caducous stipules, terminal corymbose racemes and tricolporate pollens, it is proposed here that, the species is to be placed under Rubus subg. Malachobatus ( Focke 1874: 172, 187) Focke (1910: 41).

Figures

FIGURE 1. Line drawing of Rubus haridasanii Chand. Gupta & S. S. Dash. A, Flowering twig. B, Calyx. C, L.S. of flower. D, Petal. E, Stamen. F, Pistil.

FIGURE 2. Scanned image of holotype of Rubus haridasanii Chand. Gupta & S. S. Dash

FIGURE 3. SEM images of pollen of Rubus haridasanii Chand. Gupta & S. S. Dash. A, Lateral view showing tri-colporate aperture. B, Front view along the colpus. C, Closer view of colpus showing granulations. D, Light microscope images in polar view.