Primula calderiana subsp. bawaii A. Bawri, Gajurel et Khan, 2016

Primula calderiana subsp. bawaii A. Bawri, Gajurel et Khan View in CoL subsp. nov. ( Fig. 1 View FIGURE 1 & 2 View FIGURE 2 )

Type: — INDIA. Arunachal Pradesh: West Kameng district, Naga GG , 27º17’04.8’’N, 92º10’54.9’’E, 3598 m, 25 th May 2013, A. Bawri 76; (Holotype CAL! GoogleMaps , Isotype ASSAM! GoogleMaps ).

Description: —Perennial herb. Basal bud scales ovate to ovate-lanceolate, 5–5.5 × 1–1.5 cm, yellow farinose. Leaves in a rosette; petiole broadly winged, nearly as long as leaf blade or 3–10 cm long; leaf blade broadly obovate, 5–10 × 1–5 cm; base cuneate; margin sharply denticulate, surface dark green, not farinose, lateral veins 8–12 pairs, opposite or alternate, prominent in beneath surface. Scapes 10–30 cm, farinose toward apex; umbels 4–19 flowered; bracts green, lanceolate, 0.5–1 cm, farinose. Flowers heterostylous. Pedicel 1.5–5 cm, sparsely cream-yellow farinose or glandular. Calyx campanulate, 0.5–0.8 cm, glandular, parted ½ of the length; lobes triangular; apex acute. Corolla bright yellow; tube 1.0– 1.5 cm; limbs ca. 1.5–3.5 cm wide; petals lobes broadly obovate, deeply emarginate. Anthers oblong to elongate with obtuse appendage, 0.2–0.3 cm long. Pin flowers: stamens near middle of corolla tube; style exerted up to 1.0– 1.5 cm. Thrum flowers: stamens toward apex of corolla tube; style as long as calyx or up to 0.8 cm. Capsule included in calyx.

Diagnosis: —Similar to P. calderiana subsp. strumosa in, basal bud scale being farinose and scape as well as in flower colour, but exhibiting differences in morphology of leaves, bracts, calyx and petals ( Table 1 View TABLE 1 ).

Etymology: —The epithet honors Prof. Kamaljit S. Bawa, Distinguished Professor of Biology, University of Massachusetts-Boston for his contribution to the conservation of the Eastern Himalayan flora and his special interest in Himalayan Primulas.

Ecology and phenology: —Grows in forest margins associated with Rhododendron L. (1753: 392) species at the elevation of 3900 m. Plants flowering from April to May.

Additional specimen examined:–– Arunachal Pradesh, West Kameng, Baishakhi , 20 May 2014, A. Bawri 260 ( NERIST) .

IUCN preliminary threat assessment: —Currently only known from two small areas within the type locality in West Kameng district of Arunachal Pradesh. The total known population is estimated to consist of less than 100 mature individuals. The extent of occurrence is less than 100 km 2 and we also observed a steady decline in the quality and size of habitat during the last two years. Major threats include overgrazing by Yaks ( Bos grunniens ), anthropogenic disturbance relating to resource collection and infrastructure development. Based on this information we assess this taxon as Critically Endangered (CR B1ab (iii) under the IUCN’s Categories and Criteria ( IUCN 2001, 2012). Immediate conservation efforts are necessary to prevent its extinction.

Discussion:–– Prior to this work, two morphologically variable subspecies have been recognised in P. calderiana ( Richards 2003: 117) . Primula calderiana subsp. calderiana is extremely wide spread in Eastern Himalaya including Arunachal Pradesh ( Fig. 3 View FIGURE 3 ). Our new subspecies differs from the typical subspecies in its floral and leaf morphology. It is likely that the new subspecies is more closely related to subspecies strumosa ( Fig. 4 View FIGURE 4 ) ( Richards 2003: 117), which is distributed in the altitudinal range 4000–4500 m in Eastern Himalaya. As shown in Table 1 View TABLE 1 , subspecies bawaii may be distinguished from subspecies strumosa by differences in the leaves, bracts, calyx and petal morphology.