Tuesday, February 12, 2019

[Botany • 2019] Hedychium ziroense (Zingiberaceae) • A New Species of Ginger Lily from Northeast India


Hedychium ziroense  V.Gowda & Ashokan

in Ashokan & Gowda. 2019. 

Abstract
We describe Hedychium ziroense sp. nov. from Northeast India (NE India) which was discovered during one of our recent botanical explorations in Arunachal Pradesh. We provide detailed morphological comparison of this species with four other Hedychium species (H. griersonianum R.M.Sm., H. ellipticum Buch.-Ham. ex Sm., H. gomezianum Wall. and H. yunnanense Gagnep.), with which it shares some morphological similarities. The new species is characterised by a dense cylindrical spike, pubescent rachis, folded bracts, 2–3 flowers per cincinnus, deeply cleft labellum and a distinctive late monsoonal flowering phenology from August to September.

Keywords: Apatani, Arunachal Pradesh, Hedychium, taxonomy, Ziro


Hedychium ziroense sp. nov.  C Inflorescence D Flower E Floral dissection
a Bract b Bracteole c Unopened bud d Calyx e Dorsal corolla lobe f Lateral corolla lobe × 2 g Labellum h Lateral staminode × 2 i Floral tube j Filament k Anther l Stigma m Style n Epigynous nectary × 2 o Ovary. 

 A, B Shoot and inflorescence of Hedychium ziroense sp. nov. 


Hedychium ziroense V.Gowda & Ashokan, sp. nov.

Diagnosis: Based on inflorescence shape and floral characters such as flower colour, relative length of filament to the labellum, relative length of corolla lobes to lateral staminodes and labellum, Hedychium ziroense V.Gowda & Ashokan, sp. nov. is morphologically similar to H. griersonianum R.M.Sm., H. ellipticum Buch.-Ham. ex Sm., H. gomezianum Wall. and H. yunnanense Gagnep., but it can be easily distinguished from the aforementioned species by lamina length (up to 60 cm long in H. ziroense vs. 40 cm or less in H. griersonianum, H. ellipticum, H. gomezianum and H. yunnanense), bract length (4 cm or more in H. ziroense and less than 4 cm in H. griersonianumH. ellipticum, H. gomezianum and H. yunnanense), number of flowers per cincinnus (2-3 flowered in H. ziroense vs. 1-flowered in H. griersonianum, H. ellipticum, H. gomezianum and H. yunnanense), relative lengths of bract and calyx (bract always longer than calyx in H. ziroense vs. bract length equal or less compared to calyx in H. griersonianum, H. ellipticum, H. gomezianum and H. yunnanense) and anther colour (orange in H. ziroense vs. crimson in H. griersonianum, orange-red in H. ellipticum, red in both H. gomezianum and H. yunnanense), (Figs 2, 3 and 4; Table 1).

Figure 2. Hedychium ziroense V.Gowda & Ashokan, sp. nov.
A Habitat B Habit C Inflorescence D Flower E Floral dissection a Bract b Bracteole c Unopened bud d Calyx e Dorsal corolla lobe f Lateral corolla lobe × 2 g Labellum h Lateral staminode × 2 i Floral tube j Filament k Anther l Stigma m Style n Epigynous nectary × 2 o Ovary.
Photographed by Ajith Ashokan.


Figure 3. Comparison of Hedychium ziroense and H. griersonianum.
 A, B Shoot and inflorescence of H. ziroense sp. nov. 
C H. griersonianum D Holotype of H. griersonianum R.M.Sm.

 Photo Credits: A, B Ajith Ashokan C Andrew Grierson. © Royal Botanic Garden Edinburgh 2018; D  data.rbge.org.uk  © Royal Botanic Garden Edinburgh 2018.

Distribution and habitat: This species is known only from collection along road banks on the Itanagar-Ziro road, Lower Subansiri District, Arunachal Pradesh at an elevation of more than 1700 m.

Etymology and vernacular name: The specific epithet, “ziroense”, is derived from the type locality ‘Ziro’, the closest town to where the species was found. The town of Ziro is the headquarters of Lower Subansiri District, Arunachal Pradesh. Ziro is also the name of the native tribal inhabitants of the valley much before the arrival and subsequent colonisation of Apatani tribe (Ngunu Ziro pers. com.). In Apatani language, members of Hedychium are known by the common name “papi” (Bouchery 2016).


 Ajith Ashokan and Vinita Gowda. 2019. Hedychium ziroense (Zingiberaceae), A New Species of Ginger Lily from Northeast India. PhytoKeys. 117: 73-84. DOI:  10.3897/phytokeys.117.24951

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