THE IDENTITY OF HEDYCHIUM MARGINATUM C.B. CLARKE (ZINGIBERACEAE), AND A NEW SPECIES, H. NAGAMIENSE FROM NORTH-EASTERN INDIA

The identity of Hedychium marginatum C.B. Clarke is corrected based on the type and protologue studies and H. luteum Baker is reduced as its synonym. H. nagamiense Sanoj et al. sp. nov., from Nagaland, India is described and illustrated. Nomenclatural notes, phenology, geographical distribution and IUCN status of both species are provided.


Introduction
Genus Hedychium was established by Koenig (1783) with H. coronarium as the type species, based on Rumphius' (1747) illustration.Since then, a number of taxa have been described by various authors from India and adjacent countries, mainly by Smith (1811), Roxburgh (1820), Roscoe (1824Roscoe ( -1828)), Wallich (1853), Baker (1892), Schumann (1904) and Rao and Verma (1969).Now it holds about 80 species mainly distributed in eastern Himalaya to southern China, India and south-eastern Asia (Sirirugsa and Larsen, 1995).This is the largest genus of the family Zingiberaceae in India with about 44 taxa, mostly restricted to north-eastern states (Sanoj, 2011).
During the revision of Hedychium in India, the examination of nomenclature and types of H. marginatum C.B. Clarke and H. luteum Baker revealed that both are one and the same species; hence, the latter is reduced as a new synonym of the former.A new species, H. nagamiense, is also described, which was misidentified as H. luteum by Rao and Verma (1972).A detailed description, illustration with relevant notes and a key to allied species are provided here to facilitate its identification in the field.
Flowering and fruiting: It flowers profusely in August-September and so far no fruiting has been observed.
Geographical distribution: Assam to Myanmar.In India, common in Kohima, Phek and Mokokchung districts of Nagaland but known only from solitary collections from Meghalaya, Mizoram and Tripura.

IUCN Red list Category:
The species is common at Kohima, Mokokchung and Phek districts of Nagaland (about 6,750 sq.km) and sparse at Mizoram and Tripura, and is facing high risk of threat in the wild.Hence, the species is assessed as Vulnerable (VU) [CRB1ab (i,ii,iv)+2ab (i,ii,iv)] as per IUCN guidelines (IUCN 2001, IUCN Standards and Petitions Subcommittee, 2010).Note: H. marginatum was described by Clarke (1890) based on a specimen collected by him from Kohima (C.B.Clarke 41513).He described it as a distinct species mainly because of the villous nature of the tips of bracts and yellow labellum.The plate number XXXI associated with the protologue does not match with the type material mainly on the winged filaments, bifid ligule, cylindrical inflorescence and single flowered bracts.Subsequently, Baker (1892) described another species H. luteum based on a colour plate made at Calcutta Herbarium under the supervision of T. Thomson, the then superintendant of Royal Botanical Garden in November 1854.However, H.F. Link mentioned the same epithet H. luteum long back in 1st volume of his 'Enumeratio Plantarum Beroliensis' (443.1821) under "Addenda et Emendanda" as "H.coccineum et angustifolium Bot.Mag.non differre videntur.Accepimus quoque H. luteum ex hort.angl.quod nondum floruit" (translated as -H.coccineum and H. angustifolium of the Botanical Magazine do not differ.We have also received H. luteum of English gardener which has not yet flowered).Link's species is invalid as there is not a descriptive word or a reference, as is usual with names in horticulture.While describing H. luteum, Baker (1892) did not refer to Link and he described the species only on the basis of the drawing of Thomson at CAL.The Code (McNeill et al., 2006) has no restrictions for a later use of "luteum" in the genus, and so it is quite acceptable when it was used in the 'Flora of British India'.Hence it is also difficult to say whether H. luteum of Baker and that of Link are one and the same.Later, the drawing of Thomson was reproduced by King and Prain (1898) as H. luteum, and the original illustration is available at Calcutta Herbarium.Baker (1892) placed H. marginatum under the subgenus Gandasulium Horan.(Stamen never much longer than lip) and H. luteum under the subgenus Macrostemium Horan.(Stamen much longer than lip).However, in both species, the stamens are longer than the lip (stamen rather longer than lip, and stamens half as long again as lip respectively), as evidenced by types.While describing H. luteum Baker mentioned the "labellum orbicular, bifid and distinctly clawed".This statement is a mistake made by Baker while interpreting Thomson's drawing.Based on the many live specimens from Kohima, Mokokchung and Phek districts of Nagaland and Champhai district of Mizoram revealed that, the labellum is obovate, bifid up to 8-9 mm deep and gradually clawed.Moreover it is one of the species which shows a wide range of variation in labellum size, shape and length and nature of claw.Schumann (1904) also treated H. marginatum and H. luteum under two subgenera, viz., Gandasulium and Euosmianthus K. Schum., respectively.Based on these evidences and the detailed protologue and type studies, we concluded that, both are conspecific.Recently, Rao and Verma (1972) also treated H. marginatum and H. luteum as separate species.But they misidentified and described another taxon as H. luteum.The detailed studies on the possible material used by them (D.M. Verma 34646 [ASSAM]) and the description provided turned out to be a new species.During the revisionary work of Indian Hedychium, we could collect live plants of this species from Nagaland and is described below.Diagnosis: Hedychio marginato similis bracteis apice pilis densis, sed laminis maioribus (36.5-45.0 × 6.6-9.5 contra 24.2-30.6 × 6.0-6.5 cm), inflorescentia longiore (15.5-22.0 contra 6.5-10.0 cm) cylindrica, bracteis convolutis, floribus longioribus (11.8-12.0 contra 9.8-10.2 cm) cremeoluteis, calyce longiore (4.0-4.3 contra 3.4-3.5 cm), staminis (5.5-5.7 contra 3.7-3.8 cm) differt.
Etymology: The specific epithet 'nagamiense' is derived from the name of the tribe 'Nagas', which is the prominent ethnic group of Nagaland.The type specimen belongs to Alichen, Mokokchung district of Nagaland.
Flowering and fruiting: It flowers in late August to November and so far no fruiting has been observed.
Geographical distribution: Endemic to Nagaland, India.Reported only from the type locality, one introduced material at the Woodlands, Meghalaya and Ungma, Mokokchung district of Nagaland (Chaturvedi and Moaakum, 2008).

IUCN Red list Category:
The species is known only from the type locality and another introduced plant at Woodland with unknown locality, most probably from Nagaland.It is facing high threats due to construction of roads, mining and land sliding.Due to the rarity and very restricted distribution of H. nagamiense, it is assessed here as Critically Endangered (CR) (CRB 1ab(i,ii,iii,v) + 2ab(i,ii,iii,v); D) according to IUCN guidelines (IUCN, 2001;IUCN Standards and Petitions Subcommittee, 2010).
Notes: Allied to H. marginatum C.B. Clarke in having dense hairs at the tip of bracts, but mainly differs from it in having larger lamina, longer and cylindrical inflorescence, convolute bracts, longer and creamy yellow flowers with longer calyx and stamen (Fig. 2d-f, Table 1).