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BJNRD (2023), 10(1): 57-59
Bhutan Journal of Natural Resources & Development
Open Access
www.bjnrd.org ISSN 2409–2797 (Print)
ISSN 2409–5273 (Online)
DOI: https://doi.org/10.17102/cnr.2023.85
57
BJNRD (2023), 10(1): 57-58
Notes
Maharanga griersonii (R.R.Mill) L.Cecchi & Hilger: A Critically Endangered Plant
Rediscovered after 44 years
Phuentsho1,2,*, Krishna Prasad Dhimal2,3 and Nima Dorji2
1 National Biodiversity Centre, Thimphu, Bhutan
2 College of Natural Resources, Lobesa, Bhutan
3 Mongar Forest Division, Department of Forests and Park
Services
* Corresponding author: phuentsho8@gmail.com
Received: May 17, 2023
Accepted: June 19, 2023
Published online: June 29, 2023
Editor: Ugyen Dorji (PhD)
Abstract
During a recent botanical excursion, Maharanga griersonii (R.R.Mill) L.Cecchi & Hilger formerly
Onosma griersonii R.R.Mill was rediscovered in its type locality after a gap of 44 years. Despite the
huge habitat destruction and disturbance caused by the widening of the northern east-west highway,
this critically endangered endemic plant was found thriving in the location where it was first collect-
ed in 1979. Detailed description and photographic illustrations are provided. However, detailed stud-
ies regarding its habitat and distribution are required in the future to better understand this rare spe-
cies.
Keywords: Critically Endangered, Endemic, Maharanga griersonii, Onosma griersonii
Introduction
Maharanga griersonii (R.R.Mill) L.Cecchi &
Hilger (Boraginaceae), which was formerly
placed in genus Onosma L. in the Flora of Bhu-
tan (Grierson & Long, 1999) is a species of
herbaceous plant endemic to Bhutan. Accord-
ing to the authors, genus Onosma is represented
by six species and one variety. Of the six spe-
cies, Maharanga griersonii along with Maha-
ranga bhutanica I.M.Johnst. are recorded as
endemic to Bhutan (Grierson & Long, 1999;
Yangzom & Long, 2015).
Nomenclature of Maharanga griersonii
Mill (1994) described Maharanga griersonii as
Onosma griersonii R.R.Mill with the specimen
collected by A.J.C. Grierson and D. G. Long
from Norbding below the Pelela pass in
Wangdue Phodrang District under collection
number 1080 on 16 May 1979. The holotype is
preserved in the herbarium of the Royal Botanic
Garden Edinburgh with catalogue number
E00288440 while the isotype is currently pre-
served in the herbarium of the Royal Botanic
Gardens Kew with herbarium catalogue number
K000958717 and both can be viewed online.
Long, D.G. (personal communication, Septem-
ber 27, 2021) through an email suggested that
the only other species collected at that location
was the Cupressus corneyana Knight & Perry
ex Carrière on that day. Therefore, the presence
58 Phuentsho et al., 2023
Maharanga griersonii ...
B A
of the C. corneyaya trees offered the best clue
of the whereabouts of the M. griersonii.
The species have been well described and
illustrated by Mill (1994) in his publication of
the species as a species new to science. This
description was later adopted by (Grierson &
Long (1999) in the Flora of Bhutan. The closest
relative present in Bhutan is Onosma emodi var.
emodi and O. emodi var. stelligera (I.M.Johnst.)
R.R.Mill (Figure 1a) which is now a synonym
of Maharanga vestita var. stelligera (Grierson
& Long, 1999; Mill, 1994)
According to Mill (1994), Maharanga grier-
sonii can be easily distinguished from M. emodi
and M. vestita var. stelligera in having white
flowers and by the stems which lack an indu-
mentum of shorter appressed hairs beneath the
spreading setules (Figure 1b). M. vestita var.
stelligera is currently known only from its type
collection by Ludlow and Sherriff from
Tangchu (Dangchu), Ritang, central Bhutan in
1937 under collection number 3234
(BM000798541) (GBIF.Org, 2023) and hence is
endemic to Bhutan. It was recollected by the
first author from the same locality in 2021
(Phuentsho et al., 2021).
Both Maharanga vestita var. stelligera and
M. griersonii have type localities in the
Dangchu river basin, about 16 kilometres apart
by crow's flight, with the former species at a
significantly higher altitude than the latter. M.
griersonii was given that name in honour of
Andrew J.C. Grierson, one of the authors of the
Flora of Bhutan and also one of the main per-
sons behind the project's inception along with
David G. Long.
Habitat and Ecology
A mixed forest with steep slopes (Figure 2) is
the only known locality (Grierson & Long,
1999; Mill, 1994). Cupressus corneyana and
Maharanga griersonii coexist in the same area
and the presence of natural stands of C. cor-
neyana may provide a clue to the presence of
M. griersonii in other areas. Plant species such
as Alnus nepalensis D.Don, Berberis napaulen-
sis (DC.) Spreng., Castanopsis spp., Quercus
spp., Urtica sp., and various bryophytes were
found in its habitat. Additional research may
yield a comprehensive list of allied species in
its habitat and ecology.
Conservation Status
Bhutan Endemic Flowering Plants Workshop
(2017) assessed Maharanga griersonii as Criti-
cally Endangered and possibly extinct under the
red list category as it falls under criteria B1ab
(iii) and 2ab (iii). The experts present in the
workshop concluded that M. griersonii has not
been sighted since it was discovered in 1979
and that the collection site is located near a ma-
jor national highway. The assessment panel
decided to categorise it as Critically Endan-
gered or potentially Extinct since it is known to
Figure 1: A. Maharanga vestita var. stelligera, B. Maharanga griersonii
B A
have a relatively small area of occupancy in
just one place, as well as a deteriorating extent
and quality of habitat brought under by urbani-
sation and development activities.
The rediscovery
The species was discovered by the authors on
May 14, 2023, in its type locality, below Nob-
Figure 2: Maharanga griersonii growing on
steep slopes in its habitat
ding (Norbding), at an elevation of 2502 m
(GPS coordinates are not given due to the Criti-
cally Endangered status of this species). Under
the collection number BTN682, herbarium
specimens were collected.
Conclusion
Following the first collection from Bhutan in
1979, Maharanga griersonii (R.R. Mill)
L.Cecchi & Hilger has been rediscovered after
44 years. Since it has only been sighted in its
type locality until today, we anticipate finding a
larger population and more widespread distribu-
tion in other regions of Bhutan as we continue
to explore habitats with a comparable ecology.
Ex-situ cultivation may be used to save this en-
dangered species in future. Research in future
may provide deeper understanding of the ecolo-
gy of the species.
Acknowledgements
We are highly indebted to Dr. David G. Long
from the Royal Botanic Garden Edinburgh for
providing information on this rare species.
References
Bhutan Endemic Flowering Plants Workshop. (2017). Onosma griersonii. The IUCN Red List of Threatened
Species. https://doi.org/https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T84481813A84548343.en
GBIF.Org. (2023). GBIF Occurrence Download. https://doi.org/10.15468/DL.SDN5TS
Grierson, A.J.C., & Long, D.G. (1999). Flora of Bhutan (Vol. 2 part 2). Royal Botanic Garden Edinburgh.
Mill, R. R. (1994). Notes relating to the Flora of Bhutan: XXV. Boraginaceae. I. Onosma griersonii, a new
species from Bhutan. Edinburgh Journal of Botany, 51(2), 145–146.
https://doi.org/https://doi.org/10.1017/S0960428600000834
Phuentsho, Dorji, K., Dorji, R., Tobagy, K., Sampa, & Gyeltshen, N. (2021). Following the footsteps of
George Sherriff – In search of the rare Rhododendron pogonophyllum [Unpublished report].
Yangzom, R., & Long, D. (2015). Plants Endemic to Bhutan Himalaya. National Biodiversity Centre.
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