Re-collection, extended distribution, and amplified description of Vaccinium paucicrenatum Sleumer (Ericaceae) from the Arunachal Himalaya in India

: Vaccinium paucicrenatum Sleumer has been re-collected from three different districts of Arunachal Pradesh approximately after 91 years subsequent to I.H. Burkill’s collection (no. 36976, K) from Ripsing of outer Abor Hills (presently a part of East and West Siang districts nearby Pashighat area) of Arunachal Pradesh on 8 March, 1912. Due to poor description by the earlier workers, the present paper provides amplified description based on field and herbarium data including leaf anatomy (leaf stomata and vein-islets), detailed extended distribution, live and herbarium images and distribution map for easy identification in the field.


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The genus Vaccinium L., consisting of about 140 species (Mabberley 2008), is distributed in tropical Asia, Europe, southeastern Africa, Madagascar, and north and south America. Of these, 28 species are reported to occur in India (Panda & Sanjappa 2014) and are distributed in the eastern Himalaya, northeastern India (except Tripura) and the hill tops of the southern Western Ghats.
vander Kloet et al. (2003), merged Airy Shaw's new species, Vaccinium setipes, under V. paucicrenatum Sleumer in Vaccinium sect. Aethopus Airy Shaw based on average-linkage dendrogram calculated from raw data for 76 Vaccinium OTU's (Operational Taxonomic Unit) using the dissimilarity form of Gower's co-efficient for mixed data, principal coordinates analysis, and partitioning analysis (vander Kloet et al. 2003). They re-circumscribed Vaccinium sect. Aethopus Airy Shaw not only merging V. setipes under V. paucicrenatum but also included other four species as valid and another four species as synonyms under these valid species transferring from Vaccinium sect. Vitis-idaea ( Shaw (1948) erected a new species, V. setipes, from "Assam population of outer Abor Hills, Ripshing" (Arunachal Pradesh in India) of V. paucicrenatum Sleumer based on I.H. Burkill collection (no. 36976, K photo!) which was cited by Sleumer (1941) as V. paucicrenatum in the protologue. Shaw (1948) distinguished "Assam" J TT population of V. paucicrenatum as V. setipes due to the presence of unique hispid-setose pedicels and axillary fascicled raceme which are not found in V. paucicrenatum Sleumer. Therefore, Shaw (1948) erected a new species, V. setipes under Vaccinium sect. Aethopus Airy Shaw.
As a result of taxonomic revisionary work on the Indian Ericaceae under "Flora of India Project" of the Botanical Survey of India (1999India ( -2004, as well as other national projects (UGC) on Indian Ericaceae (2009-2011) and a project (2014-16) to supervise national scholar (Rajiv Gandhi Fellow, UGC), extensive field visits were done during these periods at different localities of the eastern Himalaya including a major part of Arunachal Pradesh by the author.
From the visits, specimens from three interesting epiphytic were counted at Lohit population (7) and Lower Subansiri population (6). Based on these exomorphological and leaf anatomical data, specimens of Vaccinium L. are identified as V. paucicrenatum Sleumer. According to Airy shaw (1948), V. paucicrenatum was not reported from India. But according to vander Kloet et al. (2003), V. paucicrenatum had been reported by Sleumer (1941) based on I. H. Burkill collection (no. 36976, K) from Outer Abor Hills in 1912.

Materials and Methods
The present work is the result of an extensive field visit in different districts of Arunachal Pradesh in 2003-2014 as well as herbarium consultations in Indian herbaria (CAL, DD, ASSAM, ARUN). This work also recorded GPS points (used GARMIN eTrex 10 model) data (latitude-longitude and altitudes) during field visits. The work was carried out partly in Central National Herbarium (Voucher specimen deposited: S. Panda 30881: Lohit population) and partly in the laboratory of Angiosperm Taxonomy

Stomatal slide preparation
Small cubical pieces of leaf blades were excised from the base, middle and apex. Several existing methods viz., 10% HNO 3 -boiling for 10 minutes, 5% KOH overnight (12-24 hours) treatment without boiling and with boiling were done. Pieces were ringed in sterilized water until clear. After clearing, pieces were dehydrated in an ethanol series followed by staining with 10% safranin and mounted onto a microscope slide in DPX (pieces of basal, middle and apical regions on one slide). The slide was examined under Olympus (Tokyo: Model no. SAI740) light microscope using 10X and 40X objectives and camera lucida drawings were made with the help of a drawing prism. The slides (5 for each) are deposited in the Laboratory of Angiosperm Taxonomy, Post Graduate Department of Botany, Barasat Government College (2010) & Darjeeling Govt College (2016). The descriptive terminology follows Dilcher (1974) and Carpenter (2005).

Methodology of leaf clearing for venation study (areoles)
Entire mature leaves were immersed in 2.5% NaOH solution until clear (closed condition). In the present study, most of the leaves were cleared after eight days of NaOH treatment. After eight days, these NaOHtreated leaf samples were again immersed in 2.5% NaOH solution for 2-3 days followed by one drop chloral hydrate treatment overnight. Leaf samples were then washed in distilled water. After clearing, one good sample (entire leaf) was dehydrated in an ethanol series followed by staining with 1% safranin and mounted onto a microscope slide in DPX (entire leaf in one slide). The slides are deposited in the laboratory of Angiosperm Taxonomy, PG Department of Botany, Barasat Govt. College (2010) & Darjeeling Govt College (2016). The descriptive terminology follows Hickey (1973) and Dilcher (1974).
Leaf anatomy: Stomata (Image 5G-I): The study of Light Microscopic stomatal architecture (40X, 100X) includes number, form and arrangement of specialized epidermal cells associated with the stomatal guard cells. Stomata are distributed more or less evenly over the entire abaxial leaf surface in between the veins, but generally not over the finer veins and main veins. The stomata are uniformly distributed in abaxial surface only, they are widely separated from each other by epidermal cells.
Stomata type: The investigated species shows only one type, amphiparacytic (Dilcher 1974). Average dimension of stomata is 22.5 × 20 µm. Average dimension of guard cells: 10.3 × 2.4 µm. Epidermal cells are variable ranging from polygonal, pentagonal, rectangular to irregular and mostly isodiametric, some are elongated to deltoid. The epidermal walls in surface view are slightly arched to rarely straight. The epidermal walls in the adaxial surface are mostly straight. The maximum length of epidermal cell is 39.5µm and breadth is 22.5µm, while minimum length is 18µm and breadth is 14µm.
Habitat: A trailing profusely branched epiphytic shrub up to 1m long growing in the higher branches in the canopy, mostly on Quercus trees at altitudes ranging from 1,295-2,126 m in Arunachal Himalaya while 899-1,600 m in the hills of Myanmar (Image 1).