Journal of Threatened Taxa | | 26 March 2019 | 11(5): 13605–13610


Calamus pseudoerectus (Arecaceae), a new species from the eastern Himalaya, India


Sujit Mondal1, Shyamal K. Basu& Monoranjan Chowdhury 3


1,3 Taxonomy of Angiosperm and Biosystematics Lab, Department of Botany, University of North Bengal, Raja Rammohunpur, Darjeeling, West Bengal 734013, India.

2 The Agri Horticultural Society of India, Kolkata, West Bengal 700027, India.

1, 2, 3 (corresponding author)




Editor: K. Haridasan, Palakkad District, India. Date of publication: 26 March 2019 (online & print)


Manuscript details: #4493 | Received 14 August 2018 | Final received 01 March 2019 | Finally accepted 06 March 2019


Citation: Mondal, S., S.K. Basu & M. Chowdhury (2019). Calamus pseudoerectus (Arecaceae), a new species from the eastern Himalaya, India. Journal of Threatened Taxa 11(5): 13605–13610.


Copyright: © Mondal et al. 2019. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by adequate credit to the author(s) and the source of publication.


Funding: UGC-BSR [F. 25/1/2014-15 (BSR)/7-132/2007(BSR) dt. 07.10.2015].


Competing interests: The authors declare no competing interests.


Acknowledgements: We are grateful to authority of Herbaria at CAL, ASSAM, BSHC for access the specimens, literatures and experts opinion. We are also thankful to authority of Herbaria at K, TAI, E for open access of digital herbariums. Dr. Debobrata Maity, Department of Botany, Calcutta University, is highly acknowledged for his extensive help during article writing. First author is highly acknowledged to University Grant Commission, India, for the financial support to complete the said work.



Abstract: Calamus pseudoerectus (Arecaceae or Palmae), a new species of rattan from the hilly slopes of Mukti and Mahananda rivers at Darjeeling District of West Bengal in the eastern Indian Himalaya, is described and illustrated.  This species closely resembles two Indo-Myanmar species, C. erectus Roxb. and C. arborescence Griff.  It, however, is distinguished by its short and extremely slender stem, spine ornamentation, pendulous, long-branched inflorescence, and minute fruits with fimbriate scales.  A comparative study among C. pseudoerectus sp. nov., C. erectus Roxb., and C. arborescence Griff. is provided.  Conservation status of this species is proposed as Endangered (EN) as per IUCN.


Keywords: Calamus arborescence, Calamus erectus, new taxa, Palmae, Rattans.


Calamus L. is the largest genus of the family Arecaceae (Palmae) with about 520 species worldwide, mostly distributed in the Asia-Pacific region and Africa (Dransfield et al. 2008; Baker 2015; Baker & Dransfield 2016).  The spiny climbing and non-climbing rattans, the source of the commercial rattan cane, are distributed from tropical Africa, India to Fiji, southern China through Malay Archipelago to northern Australia (Baker & Dransfield 2014).  Calamus is most species-rich in the southeastern region of Asia, with 183 species occurring across the Malay Peninsula, Philippines, Borneo, Sumatra, and Java (Baker & Couvreur 2012; Govaerts et al. 2013) and 52 species recognized from New Guinea (Baker et al. 2002; Baker & Dransfield 2006).  Baker & Dransfield (2014) added 14 more species of Calamus from New Guinea.  The lower hills of the eastern Himalaya and the Terai parts are quite rich in Calamus species, with 28 species reported from China (Pei et al. 1991), seven from Bangladesh (Alam 1990), eight from Bhutan (Noltie 1994), and nine from Nepal (Paudel & Chowdhary 2005).  In India, Beccari (1894) reported 72 species of Calamus from undivided British India for the first time; presently, around 36 species and three varieties of Calamus are recorded from various parts of the Himalaya, Western Ghats, and the Andaman & Nicobar Islands (Basu & Basu 1987; Renuka 1987; Basu 1992).  A total of 18 species of the genus Calamus L., Plectocomia Mart. ex. Bl., and Daemonorops Bl. were reported from various altitudes of West Bengal (Mondal & Chowdhury 2018).  During exploration of palms and canes in the various lower hills and riverine forests along small streams (‘khola’) and rivers of the Darjeeling Himalaya, a few interesting specimens of Calamus were collected from Muktikhola (26049’26”N & 88013’22”E, 822m) and Choklong riverine forests (26051’42”N & 88021’45”E, 609m) of Mahananda Wildlife Sanctuary on the hillslopes of the Mukti and Mahananda rivers, respectively.  After extensive morphologic comparisons in key herbaria (Herbarium, BSI, Central National Herbarium (CAL),  Hebarium, BSI, Eastern Regional Centre, Shillong (ASSAM), Herbarium, BSI, Sikkim Himalya Regional Center, Gangtok (BSHC), and Herbarium, University of North Bengal (NBU), matching with some digital herbarium of  Herbarium, Royal Botanical Garden, Kew (K), Herbarium, National Taiwan University (TAI) Herbarium, Royal Botanical Garden, Edinburgh (E), and extensive literature search (Renuka 1987; Alam 1990; Pei et al. 1991; Basu 1992; Noltie 1994; Paudel & Chowdhary 2005; Baker & Couvreur 2012; Govaerts et al. 2013; Baker & Dransfield 2014), it was found that it is a new species for science.  The new taxon is carefully described and illustrated and a comparison of diagnostic morphologic characters with two allied Indian species, C. erectus Roxb. (Hort. Bengal. 72. 1814) and C. arborescence Griff. (Calcutta J. Nat. Hist. 5.33.1845), are presented (Table 1).  Of the 36 species in India, two species, C. erectus and C. arborescence, are completely different from the others in respect of lack of knee, cirrus, and flagella.  Similar character-bearing species from southeastern Asia are C. acaulis A.J. Hend., N.K. Ban & N.Q. Dung from Vietnam and C. oxycarpus Becc., C. macrorhynchus Burret, C. erectus Roxb., and C. dianbaiensis C.F. Wei from China.  The new species is close to this group and lacks knee, cirrus, and flagella.


Taxonomic treatments

Calamus pseudoerectus sp. nov.

S. Mondal, S.K. Basu & M. Chowdhury, 

Betgara, Otla bet [Nepali] (Image 1; Fig. 1).

Similar to Calamus erectus Roxb. and C. arborescence Griff. in respect of having similar types of ocrea and devoid of knee, flagella, and cirri, but distinct by big, branched inflorescence, minute and scattered spines, and very small fruits with fimbriate fan-shaped scales.  It further differs by having scattered spines on leaf sheath and rachis, while in C. erectus and C. arborescence, spines are clustered and whorled.  It is further characterized by pendulous big inflorescence, sheath with white and brownish-black powdery dust, conspicuous ocrea, oblong fruits, 5mm × 1mm, brown.

Holotype: 10044 (CAL), 08.ii.2018, India, West Bengal, Darjeeling District, Muktikhola hillslopes, 26049’26”N & 88013’22”E , 822m, coll. S. Mondal & M. Chowdhury.

Isotype:  Calcutta University Herbarium (CUH),  NBU (10044).

Cluster-forming rattan, erect up to 11m long.  Stem solid, with sheaths 18–20 cm diameter, without sheaths 12–13.5 cm diameter; internodes 5–9.8 cm long, 12.1–13.2 cm diameter.  Leaf ecirrate, 1.56–3.37 m long; flagella absent; sheath blackish-brown, caducous scales, sparsely variable sized blackish-brown armed with minute and few long flat spines along zone of adnation between inflorescence and sheath; knee absent; petiole 1–1.2 m long, young petiole with white powdery dust, mature petiole base with dense brown dust, covered with irregular small spines, base flat, leaf sheath closed with spongy, thick sheath fibers on both edges; leaflets 38–43 on each side of rachis; rachis 1.3–1.8 m long; glabrous, rarely spines on both edges, leaflets linear-ensiform, 41–75 cm × 2.1–4.1 cm, leaflets alternate in equidistance at base and terminal part, but opposite at middle; green beneath, narrowly elliptic to linear, mid leaflets 71–76.5 cm × 4.8–5.6 cm; apical leaflets 39.6–41.8 cm × 1.6–2.1 cm, apical leaflet scarcely united at base; fine spines 3–6 mm long, on major veins of both abaxial and adaxial surfaces; inflorescences long, looping, 2.10–2.40 m  long, non-flagelliform, branched to 1 order, one pistillate and one staminate flower lies in each node; pistillate flowers deeply embedded on rachis node, sterile staminate flowers lies at base of pistillate flowers; prophyll strictly tubular, 14–32 cm × 4.8–3.1 cm tightly sheathing, opening asymmetrically at apex, with brown indumentums similar to that of the sheath, very sparsely armed with minute recurved spines, sometimes with fine bristles around bract opening; peduncular bracts one or two, peduncular up to 1.12m long, 1.3cm diameter, with irregular spine on margin and adaxial surface, rachis bract 5.6–14.4 cm × 3.3–5.2 cm, similar to prophylls; primary branches (rachillae) 25.6–134.2 cm apart, rachillae 2–3 at each nodes; rachillae alternate, straight, 10.3–27.6 mm × 1.6–2.5 mm; rachilla bracts 1.3–1.6 cm × 2.3–2.8 cm, similar to prophylls; floral bracteoles tubular, 0.7–1.4 cm × 1.8–2.5 cm, asymmetrically opened; pistillate flowers oval, 0.6–0.4 cm × 0.4–0.5 cm, sessile, lacking indumentums; calyx 0.4cm diameter, connate at base, three-lobed; lobes 0.6cm × 0.4cm; corollatubular at base, 0.4–1.1 cm × 1.6cm long, tip three-lobed; lobes triangular, 0.6mm long; ovary globose; stigma three, prominent; sterile staminate flower narrow, 0.7cm × 0.3cm, solitary, sessile, attached at base of pistillate flowers, calyx 0.4cm diameter, connate at base, three-lobed; lobes 0.6cm × 0.4cm; tubular at base, corolla 0.4–1.1 cm × 1.6cm, tip three-lobed; lobes triangle, 0.6cm long; sterile stamens six; separate fertile male plants not seen.  Fruits very small, ellipsoid, 0.7–0.8 mm × 0.3–0.4 mm, rusty brown, with three distinct stigmatic projection, 0.1–0.2 mm long, covered with longitudinal rows of scales, reddish brown, 0.4–0.8 mm × 0.3–0.5 mm, scales not regular, fan-shaped, margins fimbriate, arranged in nine rows; one-seeded.  Seeds oblong, 0.5cm × 0.1cm, brown.

Phenology: Flowering: December–February; Fruiting: February–May.

Distribution: India (West Bengal, Darjeeling District).

Habitat: Hill slopes of riverine forests at lower hills, associated with bushes of Lantana camara L., Mikania micrantha Kunth, Pandanus nepalensis H. St. John, Curcuma aromatica Salisb., Alstonia neriifolia D. Don, and Wallichia caryotoides Roxb.

Uses: Leaves are used as thatch; local peoples use fruits for diabetes.

Etymology: The specific epithet is given as the new species is quite closer to the Indian rattan C. erectus.

Additional specimen examined (paratypes): 10212 (NBU), one specimen collected on 12.iv.2018, West Bengal, Darjeeling District, Shivkhola hillslopes, 26051’42”N & 88021’45”E , 609m, coll. S. Mondal & M. Chowdhury.

Notes: This species was discovered from the lower hills of Darjeeling District of India around 16km away from Siliguri City.  Calamus pseudoerectus is presently known from four populations in the lower hill forests of Darjeeling District of West Bengal in the eastern Himalaya.  Three populations were found at Murtikhola and one population at Shivkhola area of Mahananda WS.  Each population is with an average of 10–15 individuals.  Altogether, 40–60 individuals were observed.  We examined several pistillate inflorescences and every time found minute fruits with seeds and fimbriate scales.  The present study did not record staminate specimens.

Given the size of the area is about 60km2 (area of occupancy <500km2 and area of occurrence <5000km2), number of locations four (≤5), and threats to the habitat, we recommend Calamus pseudoerectus under the status of Endangered (EN; IUCN Standards & Petitions Subcommittee 2014).  The type locality is the part of the Himalayan hotspot (Myers et al. 2000) and faces tremendous adverse anthropologic pressure including tea gardens, road and house construction, huge forest resource collections by local people, and ecotourism.  As C. pseudoerectus grows in the open forest of Mahananda WS where human infiltration is huge due to the presence of nearby tea gardens and ecotourism sites, the existing habitat needs to be protected by the forest department for the sake of in situ conservation of this new species.


Table 1. Morphologic comparison among Calamus erectus Roxb., C. arborescens Griff., and C. pseudoerectus sp. nov.


Calamus erectus Roxb.

Calamus arborescens Griff.

Calamus pseudoerectus sp. nov.




Size (cm)


With yellow powdery dust

Dense, in oblique rows

Comb-like, whorl, dense



Powdery dust absent

Dense, in oblique rows

Comb-like, whorl



Whitish at young and blackish-brown powdery dust, sparsely variable sized armed or spines




Size (m)

Spine type




Size (m)



Dense long spines

Spine 1–2 or whorled, comb-like





Whorled, comb-like


Dense long spines

Whorled, comb-like





Whorled, comb-like


Glabrous or rarely spines

Rarely on both edge





Single, rarely on edge



Number (pair)

Size (cm)






60–80 × 3.5–5

Leaflets alternate in equidistance,

green beneath


Joined at half of their length


80–100 × 5–6

Leaflets opposite in equidistance, white beneath


Joined at half of their length



41–75 × 2.1–4.1

Leaflets alternate in equidistance at base and terminal part, but opposite at middle; green beneath

Joined at one-fourth of their length



Sizes (cm)





Tubular, short


Uniform, upper parts soft, lacerate



Papery, tattering apices

Tubular, very long


Uniform, lacerate above



Papery, tattering apices

Tubular, long


Opening wider, upper parts fibrous,



Leathery, strong


Size (m)






Short, round


Round, strongly armed with black comb-like spines


Rachillae 1 at each node, female flower rarely with sterile male flower

Pendulous, compressed


Compressed, strongly armed with black comb-like spines


Rachillae 1 at each node, female flower rarely with sterile male flower

Pendulous, compressed


Compressed, pedicle unarmed, smooth


Rachillae 2–3 at each node, each female and sterile male flower together in each node throughout

Pistilate flowers







Size (cm)






Size (mm)


Vertical rows



3–5 × 2–2.5






6–7 × 9–11

Brown, entire




2–2.2 × 0.5–0.7






6–7 × 9–11

Reddish, entire


Very small


0.7–0.8 × 0.3–0.4

Rusty brown





0.4–0.8 × 0.3–0.5

Reddish-brown, fimbriate



Size (cm)



Big, 2.7 x 1.3



Big, 1.2 x 0.6



Small, 0.5 x 0.1




For figure / image – click here




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