Wednesday, September 9, 2020

[Botany • 2020] Impatiens periyarensis (Balsaminaceae) • A New Species of Impatiens and Rediscovery of Impatiens aliciae from the Western Ghats of India


Impatiens periyarensis B. Mani, Sinj. Thomas & Britto

in Mani, Thomas & Britto, 2020. 

Abstract
A new Impatiens species, Impatiens periyarensis is described from the Western Ghats, India. It is found on the open dripping rocks in semi-evergreen forests in Idukki. Additionally, an enigmatic taxon I. aliciae, from Valara, Idukki, is rediscovered after its type collections in 1933 by Barnes. A detailed description, illustration, phenology, and notes on both the species are provided.

Keyword: Balsams, Impatiens josephia, Kerala, Travancore


Impatiens periyarensis.
 A. Habit; B. Extrafloral nectaries; C. Flowers; D. Lateral sepals; E. Dorsal petal; F. Lateral united petal; G. Lower sepal with spur; H. Stamen; I. Fruit; J. Seeds.


Impatiens periyarensis B. Mani, Sinj. Thomas & Britto, sp. nov. 

 Diagnosis: Impatiens periyarensis is similar to I. josephia Sinj. Thomas, B. Mani & Britto but differs by its spatulate and toothed extrafloral nectaries (vs. nonspatulate and non-toothed), lanceolate leaves (vs. linear), glabrous lateral sepals (vs. pubescent), funnel-shaped lower sepal (vs. boat-shaped), 1–2 mm long stout spur (vs. ca. 3 mm long tubular spur), ovate dorsal petal (vs. orbicular), ca. 1 mm long dorsal auricle (vs. ca. 2.5 mm long dorsal auricle), and ellipsoid seeds (vs. reniformdiscoid seeds). 


Etymology:
The new species is named after the Periyar River, which is the longest river in Kerala, running through the type locality. 

 Habitat and distribution: Grows on wet and dripping open rocky slopes in the semi-evergreen forests at elevations of 800–900 m. Presently, it is known only from the hill ranges of Idukki district in Kerala. 

Notes: Impatiens periyarensis is similar to I. josephia in its habit, nature of inflorescences, shape of the lateral sepals, shape of the basal lobe of the wing petals and organisation of the staminal column. However, it differs from I. josephia by various vegetative and floral characters which are depicted in Table 1. 


Impatiens aliciae.
A. Flowering branch; B. A pair of flowers; C. Flower front view; D. Lateral sepals; E. Dorsal petal; F. Lateral united petal; G. Lower sepal with spur; H. Stamen; I. Fruit.

Impatiens aliciae C.E.C. Fisch.,
 Bull. Misc. Inform. Kew 1934(9): 389 (1934) 

 Type: INDIA. Kerala, Travancore Hills, near Munnar, down the Ghat, 5000 ft., September 1933, Barnes 617 (holotype K!, K000381735 image!)  

Habitat and distribution: Grows on wet and dripping open rocky slopes and also in marshy places in the evergreen forests at an elevation of 350–600 m in Idukki, Kerala.


Bince Mani, Sinjumol Thomas and Susai John Britto. 2020. A New Species of Impatiens (Balsaminaceae) and Rediscovery of Impatiens aliciae from the Western Ghats of India. Taiwania. 65(4); 451-455. DOI: 10.6165/tai.2020.65.451