Journal of
Threatened Taxa | www.threatenedtaxa.org | 26 October 2018 | 10(11):
12607–12609
Argostemma khasianum C.B. Clarke (Rubiaceae): a
new record of a genus and species of flowering plant for the state of Arunachal
Pradesh (India) and its lectotypification
Umeshkumar L. Tiwari 1
& V.K. Rawat
2
1,2 Botanical Survey of India, Arunachal
Pradesh Regional Centre, Senki View, Papum Pare District, Arunachal Pradesh 791111, India
1 tigerumesh11@gmail.com (corresponding
author), 2 rawat_vk2107@rediffmail.com
doi: https://doi.org/10.11609/jott.3954.10.11.12607-12609
Editor: Pankaj Kumar, Kadoorie
Farm and Botanic Garden (KFBG) Corporation, Tai Po, Hong Kong S.A.R., China. Date
of publication: 26 October 2018 (online & print)
Manuscript details: Ms # 3954 |
Received 13 December 2017 | Final received 06 July 2018 | Finally accepted 11
September 2018
Citation: Tiwari, U.L. & V.K. Rawat (2018). Argostemma khasianum C.B. Clarke (Rubiaceae): a
new record of a genus and species of flowering plant for the state of Arunachal
Pradesh (India) and its lectotypification. Journal of Threatened
Taxa 10(11): 12607–12609; https://doi.org/10.11609/jott.3954.10.11.12607-12609
Copyright: © Tiwari & Rawat
2018. Creative Commons Attribution 4.0
International License. JoTT allows
unrestricted use of this article in any medium, reproduction and distribution
by providing adequate credit to the authors and the source of publication.
Funding: Botanical Survey of India, Kolkata.
Competing interests: The authors declare no competing interests.
Acknowledgements: The authors are grateful to Dr.
Paramjit Singh, Director, Botanical Survey of India
(BSI), and Dr. A.A. Mao, Head of Office, ERC, BSI, Shillong and Head of Office, BSI APRC, Itanagar
for facilities and encouragement.
Authors also thank Royal Botanical Gardens, KEW for providing herbarium
images.
Eastern
Himalaya is well known for its biological diversity, due to its varied
topography, diverse altitudinal gradient, moderate to heavy rainfall and rich
forest compositions. Among the
eastern Himalaya, Arunachal Pradesh has comparatively species rich flora when
compared with the adjoining countries like Bangaldesh,
Bhutan, China, Myanmar, Nepal. These areas known as EH biodiversity hotspot
(Brooks et al 2006). Argostemma
Wall. is a genus of small perennial herbs in the
family Rubiaceae belonging to the subfamily Rubioidae of the tribe Argostemmateae. This tribe is represented by two genera i.e.,
Argostemma Wall. and Neurocalyx Hook. (Robbrecht 1988; Sridith
1999a&b, Sridith & Puff 2000). The genus comprises 220 species (Mabberley 1997) that are distributed from Paleotropics to Africa.
The type species of this genus, A. sarmantosum
Wall., is from India.
Approximately, 106 species are reported from Bhutan, India, China,
Cambodia, Indonesia, Japan, Laos, Malaysia, Myanmar, Nepal, New Guinea,
Philippines, Thailand and Vietnam (Sridith
1999a&b).
During
a botanical exploration of the state to revise the Flora of East Kameng District, one interesting species of Argostemma with white coloured flowers and hairy
peduncle was collected. After critical
examination of the specimens and existing literature dealing with Argostemma of the Indian subcontinent and adjacent
areas (Roxburgh 1864; Hooker 1880; Hajra et al. 1996;
Pal 2013; Dash & Singh 2017) it was revealed that this genus has a new
distribution record for the state. The
species has been enumerated here along with its lectotypification,
as more than one specimen existed among the original material.
Argostemma khasianum
C.B.
Clarke in Hook.f., Fl. Brit.
Ind. 3: 43. 1880.
(Images
1 & 2)
Type:
India: Khasia Mts., F. De Silva et al. s.n. (Wallich Catalogue 8394B,
p.p., K000031008) (K!- Lectotype
designated here); 8394C-K001125382 (K!-Isolectotype
designated here).
Perennial
herb with dense matted roots.
Stem erect, branched, up to 4cm long, internodes very short, glabrous or minutely hairy.
Leaves in two pairs, pseudoverticillate,
slightly anisophyllous elliptic, apex acute, base
attenuate, 2.0–5.5 x 1.0–2.5 cm, sparsely pubescent on both surfaces; petiole
0.5–2.0 cm long, glabrous. Stipules very small,
much reduced. Inflorescence 3–6
flowered, a laxed scorpioid
cyme; peduncle 5.5–6.0 cm long, white, densely
pubescent. Flowers 4–5-merous,
actinomorphic. Calyx chartaceous,
green; calyx lobes ovate, ca. 2–3 mm long, spreading,
densely pubescent. Corolla star shaped,
pubescent outside, tip of the corolla with 4–5 hairs, corolla lobes narrowly
triangular, ca. 2mm long; corolla tube <1mm long. Stamens 4, inserted at the base of the
corolla tube; filaments ca. 6–7 mm long, free; anther fused, extrose, forming a cone like; yellow with white apical
appendage, basifixed, opening by longitudinal
slits. Ovary
pubescent; style filiform, ca. 8mm long, extrose, glabrous; stigma bilobate.
Fruits globose, pubescent.
Ecology:
On moist stream side in evergreen forests; ca. 1,500m.
Flowering:
June–July.
Taxonomic notes: Clarke (1880) while
describing this species referred to Argostemma
verticillatum, Wallich
Catalogue 8394, which was collected by ‘F. De Silva & C.’ from Khasi hills. Wallich (1829–1849) while listing his catalogue had three
sets under the number 8394, i.e., A, B & C.
Where, 8394A referred to his specimen collected from Nepal (Nipal) and 8394B-C referred to F. De Silva’s collections
from Khasia Hills in India. All these specimens were previously
identified as Argostemma verticillatum.
Among these, Wallich Catalogue 8394B in parts,
(K000031008, K001125380, K001125381) and 8394C in parts (K001125382) represent Argostemma khasianum. Of these, K000031008 is chosen as a lectotype because it contains more than one plant with both
vegetative and reproductive parts, where as K001125380, K001125381 and
K001125382 are chosen as isolectotypes.
Other specimens examined: 47315
(ARUN!), 07.vii.2016, India: East Kameng, from Bana to Yashing Top, 1,065m,
coll. U.K. Tiwari); Wallich
Catalogue 8394B - K001125380, K001125381 (K!), Khasia
Hills, F. De Silva s.n. ; Wallich Catalogue 8394C K001125382, (K!), Khasia Hills, F. De Silva s.n. ;
5472 (K!) Khasia Hills, Clarke ;
K000031014; K000031012; K000760233 (K!), Khasia
Hills, Hooker & Thompson s.n. .
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