Sunday, September 22, 2019

[Botany • 2019] Strobilanthes twangensis (Acanthaceae) • A New Species from the East Himalayas


Strobilanthes twangensis J.R.I.Wood & D.Borah

in Wood, Borah, Yama & Mipun, 2019.

Summary
A new species, Strobilanthes twangensis J.R.I.Wood & D.Borah is described from Arunachal Pradesh State in northeastern India near the border with Bhutan and Tibet. The new species is illustrated with photographs and its possible relationships with other Himalayan species are discussed.

Key Words: Arunachal Pradesh, endemic, India, Tawang

Fig. 1: A habit; B inflorescence from above; C stem showing leaves and inflorescences D leaf (adaxial surface); E leaf (abaxial surface); F inflorescence; G corolla with bract; H bract; J bracteoles; K calyx lobes; L corolla opened out to show anthers; M ovary and style.
photos: Dipankar Borah.




Strobilanthes twangensis J.R.I.Wood & D.Borah, sp. nov. 

Recognition. The small incurved, broadly ellipsoid anthers indicate this species belongs to the Goldfussia group of Strobilanthes species which is well-represented in the Himalayas. However, the white flowers and creeping habit are unusual and suggest an affinity with S. nutans (Nees) T.Anderson, which is endemic to Nepal and has similar subequal calyx lobes. The new species differs in the glabrous stem and leaves (apart from the ciliate leaf margins), the subcapitate inflorescence and in the green, foliose persistent outer bracts with a repand or undulate, ciliate margin. In S. nutans the stem and leaves are uniformly pilose, the inflorescence is formed of drooping, cone-like spikes with glabrous, deciduous, pale green, entire bracts (Wood & Adhikari 2014). The new species also somewhat resembles S. jennyae J.R.I.Wood in habit, flower colour and androecium (Wood 1994). S. jennyae grows in not very distant locations in Eastern Bhutan but is distinguished by its conspicuous pilose indumentum with large-celled, brown hairs, its lax spicate inflorescence and oblong-elliptic bracts.


Etymology. The epithet twangensis is not a misspelling of the district name Tawang but is chosen to reflect the pronunciation “twang” used by the Monpa people who inhabit the district.

Note. Strobilanthes twangensis was originally found and photographed in flower in 2017 and was collected and again photographed in flower in 2018. It appears, therefore, to be an annual flowering species like many that grow at higher altitudes such as S. attenuata (Nees) T.Anderson, S. nutans, S. lachenensis C.B.Clarke and, at least in the East Himalayas, S. atrocyanea Nees.


John R. I. Wood, Dipankar Borah, Lod Yama and Puranjoy Mipun. 2019. Strobilanthes twangensis (Acanthaceae), A New Species from the East Himalayas. Kew Bulletin. 74:41. DOI: 10.1007/s12225-019-9829-y