Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 March 2020 | 12(4): 15514–15517
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
doi: https://doi.org/10.11609/jott.5697.12.4.15514-15517
#5697 | Received 11 January 2020 | Final
received 22 February 2020 | Finally accepted 28 February 2020
Didymocarpus bhutanicus W.T. Wang (Gesneriaceae):
a new addition to the herbs of India
Subhajit Lahiri
1, Sudhansu Sekhar Dash 2, Monalisa
Das 3 & Bipin Kumar Sinha
4
1,3 Botanical Survey of India,
Central National Herbarium, Howrah, Kolkata, West Bengal 711103, India.
2,4 Botanical Survey of India, III
MSO Building, 5-6 Floor, CGO Complex, DF
Block, Sector-1, Salt Lake, West Bengal 700064, India.
1 subhajitbsi@yahoo.com, 2 ssdash2002@gmail.com
(corresponding author), 3 monalisa.bot05@gmail.com, 4 drbks2004@gmail.com
Editor: David E. Boufford, Harvard
University Herbaria, Cambridge, USA. Date
of publication: 26 March 2020 (online & print)
Citation: Lahiri, S., S.S. Dash, M. Das & B.K. Sinha (2020). Didymocarpus bhutanicus W.T. Wang (Gesneriaceae): a
new addition to the herbs of India. Journal of Threatened Taxa 12(4): 15514–15517. https://doi.org/10.11609/jott.5697.12.4.15514-15517
Copyright: © Lahiri et al. 2020. Creative
Commons Attribution 4.0 International License.
JoTT allows unrestricted use, reproduction,
and distribution of this article in any medium by providing adequate credit to
the author(s) and the source of publication.
Funding: MOEF&CC, New
Delhi (under the National
Mission on Himalayan Studies scheme).
Competing interests: The authors declare no competing interests.
Acknowledgements: Authors are thankful to the Director, Botanical Survey
of India, Kolkata for facilities; PCCF, Department of Forest, Government of
Sikkim for granting permission and logistic support. Authors are grateful to Dr. M. Moeller, Royal
Botanic Garden, Edinburgh, U.K. for his valuable comments on the identity of
species and also for providing relevant literature. Authors are grateful to the Ministry of
Environment, Forest & Climate Change (MoEF&CC),
New Delhi for financial assistance under “National Mission on Himalayan
Studies” (NMHS) Scheme (Project no. NMHS/2015-16/LG-05).
Didymocarpus bhutanicus
W.T. Wang
(Gesneriaceae), an uncommon mossy herb species
from the eastern Himalaya is reported here as a new record for Indian
flora. The species was earlier known
only from Bhutan and listed as ‘Least Concern’ in the IUCN Red List (Bhutan
Endemic Flowering Plants Workshop 2017).
A detailed description along with an image of the habitat and a photo
showing a dissected flower is provided.
A comparison with its most similar allied species, Didymocarpus
oblongus Wall. ex D.Don, is also provided for
easy identification (Table 1).
Didymocarpus Wall., with 60 species worldwide, is
mainly distributed in Nepal, Bhutan, northeastern India, Myanmar, southern
China, Vietnam, Laos, Cambodia, Thailand, and the Malay peninsula. It is represented by 23 species in India,
mainly restricted to the northeastern regions (Moller et al. 2016). The taxonomy and delimitation of Didymocarpus has varied considerably from time to
time (Burtt 1998; Weber et al. 2000, 2011; Möller et al. 2011; Möller &
Clark 2013; Li et al. 2016) and the circumscription of its members have also
been subjected to various changes based on molecular phylogenetic studies and
morphological revisions (Xu et al. 2019).
Recent studies reveal the need for taxonomic rearrangement of the
members, particularly those in northeastern India and in southeastern Asia
(Weber & Burtt 1998; Möller
et al. 2016).
During
a floristic and ecological study in Sikkim in July 2019, under the auspices of
the project entitled ‘Biodiversity Assessment through Long Term Monitoring
Plots in Indian Himalayan Landscape’ an isolated population of an interesting
species of Didymocarpus Wall. was
discovered near Radong, East District, Sikkim (Figure
1). Through a survey of literature (Wang
1983; Wang et al. 1998; Weber et al. 2000; Hilliard 2001) and a comparison of
herbarium specimens at ARUN, BSHC, CAL, we identified the plants as Didymocarpus bhutanicus
W.T. Wang, a species hitherto not reported from India. A detailed description of D. bhutanicus along with a field photograph (Image 1),
locality map (Figure. 1) and notes are provided. The presence of D. bhutanicus
in Sikkim also establishes an eastward extension of its range.
Macro
and micro morphology of dissected floral parts were observed using an Olympus
stereo-zoom dissecting microscope (Olympus SZ61). Photographs were taken in the field with a
Sony HX 400V Camera. The coloured photo plate was made using Adobe Photoshop CS3;
the locality map was created by using Arc Map (ver. 10.1) and Google Earth Pro.
Didymocarpus bhutanicus
W.T.
Wang,
Bull.
Bot. Res., Harbin 3(4): 46. 1983.
Type:
E. Bhutan, Trashi Yangsi
Chu, Tobrang, 2,600m, on mossy stones, in dense mixed
forest, 5 July 1949, F. Ludlow, G. Sherriff and J.H. Hicks n. 20840 (Holotype,
TI) (digital image!).
Herbs,
erect, perennial. Roots woody, fibrous.
Stem erect, 9–12 cm long, spreading, light brownish puberulous. Leaves 4, sub-verticillate, distal on stem;
petiole 1.4–2.8 cm long; lamina herbaceous, slight unequally oblong or narrowly
oval, 3.5–12 × 2.6–5 cm, base obliquely cuneate or obliquely rounded, margin
double toothed, apex acute to acuminate, abaxially puberulous,
adaxially glabrous or appressed puberulous, midvein
prominent, lateral veins 5–7 pairs.
Inflorescences cymes, axillary, peduncle 7.5 ̶ 9.5 cm long, 2 or 3 times
branched, distally spreading puberulous, ca. 6–10
flowered; bracts opposite, rounded-oval, 7.5 ̶ 8 × 7–9 mm. Flowers: calyx campanulate, ca. 5mm long,
light pink, glabrous, 5 ̶ lobed, lobes 1.4 ̶ 2.1 mm long, obtuse; corolla pink
or pale lilac, 1.7 ̶ 2 cm long, glabrous, tube cylindrical, lower lip
suborbicular, 8.5 ̶ 9 mm long, 9 ̶ 10 mm wide, 3-lobed; stamens inserted 2.3 ̶
3.5 mm above base of corolla, anthers oval, dorsifixed,
glabrous; ovary lanceolate 2–3.8 mm long, stigma disciform. Capsule 1.8–2.3 cm long.
Flowering
and fruiting: July-–August.
Habitat
and ecology: In wet moss-covered rocky crevices; 2,000–2,300 m. Main associated species: Caulokaempferia
sikkimensis (King ex Baker) K. Larsen, Impatiens
purpurea Hand.-Mazz.,
Lycopodium japonicum Thunb., Adiantum incisum Forssk.
Distribution:
Bhutan; India (Sikkim).
Conservation
status: Least Concern (Bhutan Endemic Flowering Plants Workshop 2017).
Specimen
examined: 95701, 01.vii.2019, India, Sikkim, East District, near Rakdong, 27.3850N & 88.5280E,
2,100m, coll. S. Lahiri & M. Das (CAL!) (Image
2).
Notes: Didymocarpus bhutanicus is morphologically similar to D.
oblongus
Wall. ex D.Don. Both species occur between
1,500 and 3,000 m elevation. Both have
well-developed stems and a pink corolla. Didymocarpus bhutanicus can be differentiated from D.
oblongus by
the longer peduncle, larger flowers and longer petiole. The leaves are rounded and densely puberulous to villous in D.
oblongus; D. bhutanica has
oblique, rounder leaves glabrous on the adaxial surface.
For figure & images - - click here
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