Journal of Threatened
Taxa | www.threatenedtaxa.org | 26 January 2025 | 17(1): 26440–26442
ISSN 0974-7907 (Online)
| ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.9164.17.1.26440-26442
#9164 | Received 28 May
2024 | Final received 11 November 2024 | Finally accepted 29 November 2024
A
note on Pterospermum obtusifolium
Wight ex Mast. (Malvaceae), a rare endemic evergreen tree of
southern Western Ghats, India
K. Narayanan 1 &
Shamsudheen Abdul Kader 2
1,2 Department of Plant
Biology and Plant Biotechnology, Presidency College (Autonomous), Chennai,
Tamil Nadu 600005, India.
1 narayanan01031995@gmail.com,
2 sakfri@rediffmail.com (corresponding author)
Editor: Mandar Nilkanth Datar, MACS-Agharkar Research Institute, Pune, India. Date
of publication: 26 January 2025 (online & print)
Citation: Narayanan, K. & S.A. Kader (2025). A note on Pterospermum
obtusifolium Wight ex Mast. (Malvaceae),
a rare endemic evergreen tree of southern Western Ghats, India. Journal of Threatened Taxa 17(1): 26440–26442. https://doi.org/10.11609/jott.9164.17.1.26440-26442
Copyright: © Narayanan & Kader 2025. 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: None.
Competing interests: The authors declare no competing interests.
Acknowledgements: The authors are thankful to online websites such as British Heritage Library and Internet Archive for accessing original publications. They are also thankful to the officials of the Tamil Nadu Forest Department for permitting us to enter the reserve forest for the study.
The genus Pterospermum Schreb.
belonging to Malvaceae sensu lato family
(formerly Sterculiaceae) comprises of 52 accepted and
25 unresolved species (POWO 2024). In India, it is represented by 11 species
(Chandra 1993) of which eight species are distributed in southern India: P. reticulatum Wight & Arn.,
P. obtusifolium Wight ex Mast., P. heyneanum Wall. ex Wight & Arn.,
P. diversifolium Blume, P. rubiginosum Heyne, P. suberifolium (L.) Lam., P. acerifolium
(L.) Willd. (Gamble & Fischer 1935), and P.
xylocarpum (Gaertn.) Santapau & Wagh (Narasimhan
& Sheeba 2021). Among them, P. obtusifolium Wight ex Mast., and P. rubiginosum Heyne are endemic
to the southern Western Ghats, and are found growing in the evergreen forests
(Gamble & Fischer 1935), the former is rare (Britto 2019) while the latter
is common (Rao et al.
2019).
Pterospermum obtusifolium Wight ex Mast. is a tree, grows primarily
in the wet tropical biome and its native range is southwestern India (WFO
2024). It was first collected by Robert Wight in 1838 from Courtallum
(then Tirunelveli District), Tamil Nadu, and published in 1840 in
‘Illustrations of Indian Botany’. Later, although, it has been reported from
Karnataka, Kerala, and Tamil Nadu (Sasidharan 2011;
Singh et al. 2015; Britto 2019; Rao et al. 2019), no new herbarium collections
including fresh specimens images are available. Only
six herbarium specimens of Robert Wight are available but none of them
were found in Indian Herbaria, of which Wight 227 is well preserved at Kew
[K000671799] and hence it was designated as lectotype and remaining as syntypes
by Rekha et al. (2020) recently. During our revisionary work on Pterospermum species of peninsular India, the
species was collected from its type locality in the year 2023.
Pterospermum obtusifolium Wight ex Mast. (Image 1) was collected
from two locations (Chitaruvi and near Shri Shenbaga Devi Temple) in Courtallum,
Sengottai Forest Division, Tenkasi
District of Tamil Nadu and identified with the help of local flora, BSI
publications, and consulting Virtual Herbarium, Kew. Required taxonomic
characters including flowering and fruiting phenology were recorded for
detailed botanical description and herbaria prepared. Data were also gathered
from the literature for analysis. Ahmedullah & Nayar (1987) have reported that it is endemic to southern
Western Ghats in Travancore, Tirunelveli, Coimbatore, Ramanathapuram
and Tiruchirappalli. Based on this information, later workers like Rao et al.
(2019), Britto (2019), and Narasimhan & Sheeba
(2021) have documented only these areas for distribution of this species in
their compilation works, without specifying exact collection localities.
Similarly, Sasidharan (2011) too documented it for
‘Flowering Plants of Kerala’ without specifying exact collection localities.
Therefore, it seems that none of them have collected this species again from
these areas. Recently, Rekha et al. (2020) have lectotypified
it using Wight’s collections deposited at KEW. The
prepared herbarium sheets (PCM KN09 dated 07.iv.2023) were deposited in Madras
Presidency College (PCM), Madras Herbarium (MH) at BSI Coimbatore, and
Fischer’s Herbarium (FRC) at IFGTB Coimbatore.
Botanical description
Habit: a large evergreen tree (Figure 1),
attaining more than c. 2.13 m GBH. Leaves: simple, alternate, petiolate
(petiole 5–15 mm long), three-nerved at base, oblique, cuneate-obovate to
cuneate-oblong, margin entire, base cuneate, either very broadly truncated at
tip, somewhat obcordate, or irregularly
two-lobed at tip, lobes coarsely toothed, upper surface green and
glabrous (Image 1), lower surface glaucous pubescence (Figure 1), 5.9–17 cm ×
3.1–8.2 cm, lateral veins 5–6 pairs (usually five pairs), prominent, distant (Image 1).
Inflorescence: axillary cyme. Flowers: flower bud, oblong-angular,
shortly-pedicellate, pedicel 4 mm long; medium-sized, white, fragrant, 4.0–4.5
cm across (Image 1). Calyx: sepals five, green, free, recurved, linear with
round tip, 1 mm thick, stellate-tomentose, longer
than the petals, 3.7 × 0.4–4.5 × 0.7 cm in size (Image 1). Petals: white,
oblanceolate, thin, densely stellate-pubescent outside, 2.7 × 1.0–3.4 × 1.3 cm
in size (Image 1). Androecium: staminodes five, 2.3 cm long, white; stamens 15,
arranged in bundles of three
each in between staminodes, filament white, short, 9 mm long;
anthers 7 mm long (Image 1). Gynoecium: pistil white, ovary pentacarpellary,
5 × 4 mm in size; style 2 cm long, stigma 5 mm long (Image 1). Fruit: a woody dehiscent
capsule, medium-sized, stalked, stalk 2–2.2 cm long, oblong, 6–6.5 cm × 2.8–3.5
cm, surface rough and tubercled, tip obtuse,
4–5-seeded (Image 1). Seed: brown, 5–13 mm long; wing brown, knife-shaped, tip
round or acute, 1.5–3.1 cm × 5–11 mm (Image 1).
Flowering: March–April.
Fruiting: April–May.
For
image - - click here for full PDF
References
Ahmedullah, M. & M.P. Nayar
(1987). Endemic
Plants of the Indian Region. Vol. 1. Peninsular India. Botanical
Survey of India, Calcutta, 261 pp.
Chandra, S.K. (1993). Pterospermum Schreb.
nom. cons., pp. 447–454. In: Sharma, B.D., M. Sanjappa
& N.P. Balakrishnan (eds.). Flora of India, Vol. 3. Botanical
Survey of India, Kolkata, 639 pp.
Gamble,
J.S. & C.E.C. Fischer (1935). Flora of the Presidency of Madras (Reprint). Vol. I. Bishen Singh Mahendra Pal Singh,
Dehra Dun, India, 577 pp.
Britto,
J.S. (2019). The
Flora of Central and North Tamil Nadu. Part – 2: Fabaceae – Loranthaceae
(APG – IV). The Rapinat Herbarium, St. Joseph’s
College (Autonomous), Tiruchirappalli, south India, pp. 1403–1404.
Narasimhan,
D. & J.I. Sheeba (2021). Flowering Plants of Tamil Nadu: A
Compendium. Tamil Nadu Biodiversity Board, Chennai, 1114 pp.
POWO
(2024). Pterospermum Schreb.
http://powo.science.kew.org. The Royal Botanic Gardens. Accessed 13.viii.2024.
Rekha,
G., G. Gnanasekaran & D. Narasimhan (2020). Lectotypification
of two names in Pterospermum (Malvaceae). Rheedea 30(2):
317–318.
Rao,
K.S, R.K. Swamy, D. Kumar, R.A. Singh & K.G. Bhat (2019). Flora of Peninsular India. http://peninsula.ces.iisc.ac.in/plants.php?name=Pterospermum
rubiginosum. Accessed 04.xi.2024.
Sasidharan, N. (2011). Flowering Plants of Kerala. DVD, Vol.2. Kerala Forest Research
Institute, Peechi.
Singh,
P., K. Karthigeyan, P.L. Narasimhan & S.S. Dash
(2015). Endemic
Vascular Plants
of India. Botanical Survey of India, Kolkata, 245 pp.
WFO
(2023). http://www.worldfloraonline.org.
Accessed 23.v.2024.
Wight, R. (1840). Illustrations of Indian Botany; or
Figures Illustrative of Each of the Natural Orders of Indian Plants - Vol. 1.
J.B. Pharoah, Madras, 78 pp.
Errata
Citation: Chaudhary, K.O. (2024). Diving
into diversity: aquatic beetles of Sukhna Wildlife
Sanctuary, Chandigarh, India. Journal of Threatened Taxa 16(11):
26124–26130. https://doi.org/10.11609/jott.8963.16.11.26124-26130
In the article “Chaudhary, K.O. (2024)
three references printed are incorrect. The correct citations are as follows:
Ribera, I. & G.N. Foster & A.P.
Vogler (2003). Does
habitat use explain large scale species richness patterns of aquatic beetles in
Europe? Ecography 26: 145–152. https://doi.org/10.1034/j.1600-0587.2003.03271.x
Akünal, A. & E.G. Aslan (2017). Ecological investigations on Hydrophilidae and Helophoridae (Coleoptera) specimens gathered from several water bodies of
Western Turkey. Knowledge and Management of Aquatic Ecosystems 418(43):
6. https://doi.org/10.1051/kmae/2017035
Lundkvist, E & J. Landin, M. Jackson & C. Svensson (2003). Diving beetles (Dytiscidae)
as predators of mosquito larvae (Culicidae) in field
experiments and in laboratory tests of prey preference. Bulletin of
Entomological Research 93(3): 219–226. https://doi.org/10.1079/BER2003237