Arisaema attenuatum E.Barnes & C.E.C.Fisch., Bull. Misc. Inf. Royal Gard. Kew 1936

Arisaema attenuatum E.Barnes & C.E.C.Fisch., Bull. Misc. Inf. Royal Gard. Kew 1936 View in CoL (4): 275. 1936; Chatterjee, Bull. Bot. Soc. Bengal 8: 121. 1955; Manilal, Fl. Silent Valley 331. 1988; Sivad. in Manoharan et al., Silent Valley-Whispers of Reason. 233. 1999. Type: INDIA , Kerala, Idukki district , Munnar , s.d., E. Barnes 1193 ( K000203014 digital image!).

A. leschenaultii auct . Gusman & L.Gusman, Gen. Arisaema ed. 2. 392. 2006, pro parte, non Blume 1836. Fig. 3 View Figure 3

Deciduous, dioecious, succulent, perennial herbs, 40–65 cm tall. Subterranean stem a tuberous corm, subglobose, 3–5 cm diameter, 2–3 cm tall, smooth or wrinkled, tuberlets often present, surrounding the pseudostem. Roots arising from the upper side of the corm. Cataphylls 3 or 4, acute-obtuse at apex, slightly keeled towards tip, decidedly mucronate; outer 2–3 cm long, pale coloured; middle c. 9 cm long, light green with brownish-purplish and flesh coloured patches; inner c. 21 cm long similar to middle-one, dark coloured; often a degenerated outer cataphyll also present. Leaf solitary, radiatisect, emerging after the inflorescence; petiole slender, up to 65 cm long, light green mottled with brownish-purple patches; leaflets 7–9, sessile, oblong-lanceolate, sometimes oblanceolate, 15–21 cm long, 3.5–4.2 cm wide, narrowly acute to tapering, margins minutely praemorse, with a purplish dorsal border, dark green ventrally, pale dorsally, midvein often mottled with purplish spots. Pseudostem 25–30 cm long, mottled as in petiole. Inflorescence held below the leaf; peduncle slender, 30–35 cm long, exserted by about 4–5 cm from the sheathing pseudostem, dark purplish or green-greenish white. Spathe 6.5–12 cm long; tube of spathe cylindric, slightly funnel-shaped towards the mouth, 6.5–7 cm long, 1–1.5 cm wide, white or greenish white basally and greenish towards the distal end with purplish-brown bands along the length of the tube, bands lighter outside, darker inside; purple bands often absent in male plants where it is replaced by green bands outside; margins of the mouth decidedly revolute; limb, short, triangular, elongate-lanceolate, narrowly acuminate to tapering, 2–5 cm long, 1.5–2.5 cm wide, green with a large roundish white patch at base with radiating stellate arms, few purplish markings at the junction of the green and white, tail erect or arching forward and pointing downwards. Female spadix sessile, 8–10 cm long, 0.2–0.3 cm thick, exceeding the tube and arching forward; female fertile region 2–2.5 cm long; pistils many, crowded, sessile, subglobose, green; ovules 2 or 3; style short or absent; stigma papillate, stellate, often with a dark bluish neck; neuters subulate, few, 2–3 mm long, scattered over a distance of 2–3 cm, upcurved, completely purple or off-white with a purple tip; appendix slender or filiform, tapering distally, green or purplish buff towards the base, becomes greenish towards the distal end, often with a warty, purple tip. Male spadix sessile, slender, similar to female, 5.5–8.7 cm long, 0.3–0.5 cm thick; male fertile region 2–3 cm long; male flowers scattered over or crowded at the base, distant above, 2–4-androus; anthers sessile, purple, dehisce by an apical pore; pollens spherical, slightly echinate, purple; neuters usually absent, rarely 1 or 2 present. Fruiting spike not seen.

Flowering: May–June.

Habitat: In grasslands and in shola forests at an elevation above 1200 m, together with A. peltatum , A. leschenaultii and A. tortuosum .

Distribution: India (southern Western Ghats), endemic.

Specimens examined: INDIA , Kerala, Idukki district, Devikulam , c. 1800 m, 27.07.1982, N. Sasidharan 4173, 4178 ( KFRI!) ; Lockhurt gap, Munnar-Poopara road, 23.05.2011, Manudev & Santhosh Nampy 4430, 4431 ( CALI!) ; ibid., 25.05.2012, Anisha & Manudev 4563 ( CALI!) ; Mathikettan shola, Aduvizhuntha kudi, 22.11.2014, Syam Radh & Rajeevan , 137822, 137824 ( CALI!) ; Checkpost to Onnam Thodu, Mathikettan , 22.05.2015, Manudev & Syam Radh 138959 ( CALI!) ; Choondal, Mathikettan , 23.04.2016, Syam Radh & Arunkumar 149117 ( CALI!) ; Ettukalichelamaram to Check post, 22.05.2015, Manudev & Syam Radh 138957 ( CALI!) ; Onnamthode, Mathikettan , 08.05.2016, Syam Radh 137976, 137979 ( CALI!) ; Pallivasal , 24.05.2011, Manudev & Santhosh Nampy 4438 ( CALI!) ; Sivan Para, Mathikettan , 23.08.2014, Syam Radh & Prashob 143502 ( CALI!) ; Pothamedu , c. 1100 m, 25.07.2013, Manudev 135307 ( CALI!) . Tamil Nadu, Coimbatore district, Anamalai hills, 26.06.1973, R. N. Kayal & H. N. Tribedi 569 ( CAL!) .

Notes: Arisaema attenuatum was described by Fischer (1936) from the collections of Professor Edward Barnes from Munnar High ranges. Gusman and Gusman (2006) treated this species as a synonym of A. leschenaultii , a common species distributed throughout the Western Ghats showing significant variation. However, it is distinct from the latter in having shorter spathe limb with a basal white spot and slender spadix appendix.

Conservation status: The population size of A. attenuatum thriving at the Devikulam and Lockhurt Gap is very scanty with about less than 10 mature individuals; while at the Pallivasal, 25 mature individuals were observed and at the Mathikettan shola National Park about 65 individuals. There are a few specimens at CAL collected from Anamalai hills of Tamilnadu region, not far away from the type locality. Based on ‘Extent of Occurrence’ (EOO<100 km 2; Criterion B1), ‘Area of Occupancy’ [Criterion B2: AOO<10 km 2 with extreme fluctuations in number of subpopulations [sub-criterion ‘c (iii)’], and number of mature individuals (Criterion C), A. attenuatum is assessed here as ‘CRITICALLY ENDANGERED’ [CR: B1, B2b(iii), B2c(iii) & C2b.] according to IUCN’s guidelines (IUCN SPS, 2017). This species is threatened due to habitat loss mainly by the conversion of forest areas in to tea plantations in Munnar regions.