Henckelia ovalifolia (Wight) A.Weber & B.L.Burtt, Beitr. Biol. Pflanzen

A. P., Janeesha & Nampy, S., 2020, A taxonomic revision of Henckelia (Gesneriaceae) in South India with a new species, one new combination and seven lectotypifications, Rheedea 30 (1), pp. 48-95 : 79-82

Henckelia ovalifolia (Wight) A.Weber & B.L.Burtt, Beitr. Biol. Pflanzen 70: 351. 1998 [“1997”]; T.S.Nayar et al., Fl. Pl. Western

Ghats 1: 529. 2014; Janeesha & Nampy, Phytotaxa 268(1): 84. 2016. Didymocarpus ovalifolius Wight, Icon. Pl. Ind. Orient. 4: 24. t. 1351. 1848, Ill. Ind. Bot. 2: 131. t. 142, fig. 6. 1850; C.B.Clarke in Hook.f., Fl. Brit. India 4: 354. 1885 [“1884”]; Rama Rao, Fl. Pl. Travancore 295. 1914; Gamble, Fl. Madras 2: 988. 1924; M. Ahmedullah & M.P.Nayar, Endemic Pl. Indian Region 1: 143. 1987; A.N.Henry et al., Fl. Tamil Nadu Ind., Ser I: Analysis 2: 132. 1987; Manilal, Fl. Silent Valley 200. 1988; M.Mohanan & A.N.Henry, Fl. Thiruvananthapuram Dist. 338. 1994; Gopalan & A.N.Henry, Endemic Pl. India 117. 2000; M.Mohanan & Sivad., Fl. Agasthyamala 495. 2002; Sasidh., Biodivers. Doc. Kerala part 6: Fl. Pl. 332. 2004; T.S. Nayar et al., Fl. Pl. Kerala 342. 2006. Roettlera ovalifolia (Wight) Kuntze, Revis. Gen. Pl. 2: 476. 1891. Lectotype (designated by Janeesha & Nampy, 2016): INDIA, Tamil Nadu, Courtallam, 08.1835, Wight 558 (E [E00155178 digital image!]; isolecto E [E00179262 digital image!], K [K000858199 digital image!]). FiG. 18

Perennials, rosette-forming herbs with rootstock. Roots adventitious. Stem reduced. Leaves 8–18, decussate; petioles 4–14 cm long, hairy throughout, not winged; laminae usually ovate-broadly ovate, rarely orbicular, 3.3–12.8 × 2.5–7.7 cm, slightly acute to obtuse at apex, unequal at base, margins crenate to serrate, white strigose or tomentose above and on the lower veins; veins 7–10 on each side, much branched and conspicuous beneath. Cymes axillary, 2–5 per plant, 2–3 times divided, 6–8- flowered; bracts two, oblanceolate, 6.38 × 1.34 mm, white tomentose hairy out; peduncles terete, 9–22.5 cm long, green-pale reddish brown, hairy throughout; pedicels terete, 5–10 mm long, narrow, hairy. Flowers 12–20 × 8–15 mm. Calyx 5-partite, very deeply divided or basally connate; lobes linear to lanceolate, unequal, posterior lobe small, 4.2– 5.1 × 0.8–1 mm, others 5.8–6.8 × 1.1–1.2 mm, slightly acute at apex, margins entire, reddish brown, white tomentose outside. Corolla zygomorphic, ventricose, two lipped, white hirsute outside, glabrous inside; tube 7.2–11.3 × 5–5.8 mm, very pale violet to brilliant purple, deep purple at the throat and a yellow blotch at the base of the tube; lobes very widely ovate, slightly acute to obtuse at apex, violet to brilliant purple, upper lip of two lobes, 6.5–7.2 × 5.8–6.6 mm, lower lip of three lobes, 8–8.4 × 7.1–7.25 mm. Stamens 2, adnate to the base of the corolla, included; filaments 5.3– 5.7 mm long, puberulent towards the apex, light yellowish green towards the top and milky white towards the base; anthers reniform, 1.7–1.9 × 0.65– 0.8 mm, yellowish brown, glabrous. Staminodes 2; filaments 3.5–3.7 mm long, hyaline, glabrous; antherodes not prominent. Ovary narrowly ovoid to cylindrical, tapering to a style, 4.9–5 × 1.1–1.21 mm, green towards the base and reddish brown towards the apex, hairy; style terete, 4–4.1 × 0.35– 0.40 mm long, hyaline, hairy throughout up to the middle; stigma obliquely subcapitate, 0.68 × 0.38 mm, papillate, milky white. Capsules linear, straight, 36–44 × 2–2.2 mm, plagiocarpic, dehiscing loculicidally along the dorsal side, reddish brown, hairy with persistent stigma and calyx. Seeds numerous, elliptic, 0.49–0.59 × 0.21–0.24 mm, acute at apex, truncate at base; testa dark brown, reticulate.

Flowering & fruiting: Flowering from June to September and fruiting from August to October (up to February).

Habitat: In moist shady areas of dense evergreen forest, in humus rich soil or on fallen, moss covered tree trunks. Grows in association with Impatiens travancorica Bedd. ( Balsaminaceae ), Christella sp. ( Thelypteridaceae ), Osbeckia sp. ( Melastomataceae ) and some grass species.

Distribution: Endemic to the southern Western Ghats ( Fig. 17 ).

Specimens examined: INDIA, Kerala, Idukki district, Kallar Reserve Forest, 16.07.1989, s.coll. 90687 (MH); Periyar–Koruthode, 25.09.1996, Jomy Augustine 16811 (CALI); Kollam district , Thenmala, 15.06.1984, N. Mohanan 165 (TBGT); Palakkad district , Nillikkal South, 08.06.1982, Prasannan 10392 (CALI); Thiruvananthapuram district , Agasthyamala, 24.06.1993, N. Mohanan 11454 (CALI, TBGT); Ibid., 19.10.1993, G. Gangaprasad & S. William Decruse 18419 (TBGT); Ibid., 06.06.2014, K.M. Manudev & A.P. Janeesha 138919, 138925; Ibid., 21.10.2016, K. Shinoj & A.P. Janeesha 137658 (CALI); Pongalapara, 25.08.1990, N. Mohanan 10044 (TBGT); Ponmudi, 10.10.2014, K.P. Vimal, M.G. Prasad & A.P. Janeesha 137602 (CALI); Western slopes of Agasthyamala, 06.10.1973, J. Joseph 44608 (MH); Wayanad district , Gurukula botanical sanctuary (cultivated), 25.11.2014, A.P. Janeesha & S. Resmi 137609; Periya, 25.08.1984, R.T. Balakrishnan 40450; Thalapaya, 10.02.1986, R.T. Balakrishnan 41944 (CALI) . Tamil Nadu, Kanyakumari district, Muthukuzhivayal, 06.08.1977, A.N. Henry 49610 (MH); Ibid., 01.09.1981, K.M. Matthew 17788 (RHT); Tirunelveli district , Agasthyamala, 22.06.1901, C.A. Barber 2918; s.loc., 1807, R.H. Beddome 164 (MH). Conservation status: This species is known from eight locations in seven districts in Kerala and Tamil Nadu with a narrow South-North distribution. The estimated Extent of Occurrence (EOO) is c. 1100 km ² and Area of Occupancy (AOO) is 32 km ². The authors surveyed three locations and found a total of only 81 mature plants. Since these locations are inside protected areas, the chances for a decline due to anthropogenic activity is small. The situation of just under half of the localities is known. However, when extrapolating the findings on mature plants to the entire distribution range, it may justify categorisation of the species as Endangered (EN), D ( IUCN, 2019) .

Notes: Henckelia ovalifolia and H. missionis are similar in having simple ovate, long petioled leaves, large flowers and long fruits. However, H. ovalifolia can be identified by its leaves with serrate margins and strigose hairs, scapes hairy throughout, hirsute corolla, puberulent filaments and a hairy style.

Figures

FiG. 18. Henckelia ovalifolia (Wight) A.Weber & B.L.Burtt: a. Plant in natural habitat; b. Habit; c. A portion of the inflorescence; d. Flower; e. Calyx; f. Calyx with pistil; G. Bract; h. Stamens; i. Staminode; j j.j.. Pistil; k. Immature capsule; L. Seeds (a from K.P Vimal, M.G. Prasad & A.P. Janeesha 137602; b-L from K.M. Manudev & A.P. Janeesha 138919).

FiG. 17. Distribution of Henckelia lyrata (Wight) A.Weber & B.L.Burtt, H. macrostachya (E.Barnes) A.Weber & B.L.Burtt, H. meeboldii (W.W.Sm. & Ramaswami) A.Weber & B.L.Burtt and H. missionis (Wall. ex R.Br.) A.Weber & B.L.Burtt in South India (drawn using QGIS v.3.12.1).