Lindernia dubia (Linnaeus) Pennell, 1935

Prasad, Mangavayal Govindan & Sunojkumar, Purayidathkandy, 2014, First record of Lindernia dubia (Linderniaceae) in India and reduction of Lindernia nelliyampathiensis as one of its synonyms, Phytotaxa 187 (3), pp. 165-169 : 166

Lindernia dubia (L.) Pennell (1935: 141) ( Fig.1 )

Basionym: ─ Gratiola dubia Linnaeus (1753: 17)

Type : ─ UNITED STATES. Virginia: J . Clayton 164. (Lectotype BM!)

= Gratiola anagallidea Michaux (1803: 6) ≡ Lindernia anagallidea (Michx.) Pennell (1935: 152) ≡ Lindernia dubia var. anagallidea (Michx.) Cooperrider (1976: 224)

= Ilysanthes riparia Rafinesque (1820: 13) ≡ Lindernia dubia var. riparia (Raf.) Fernald (1942: 444)

= Lindernia nelliyampathiensis Sunil et al. (2014: 136) syn.nov.

Type: ─ INDIA: Kerala Palghat District, Nelliyampathi , Karappara , 12 March 2012, C. N . Sunil , V . Abdul Jaleel & M. K . Ratheesh Narayanan 4904 (Holotype MH!)

Annual, stout, erect or sometimes ascending herb, rooting at the lower nodes; stem quadrangular, glabrous, much branched near base. Leaves sessile, basal ones larger, smaller towards apex, 0.5 − 2.5 × 0.2 − 1.5 cm, ovate or ovateelliptic, upper ones narrowly ovate to lanceolate, 3 − 5 veined from base, veins distinct on lower larger leaves, base cuneate-attenuate or rounded, apex acute to acuminate, occasionally obtuse, margin entire or shallowly 2 − 3 toothed, largest leaves near base. Flowers solitary, axillary, pedicel slender, 4-angled, sparsely glandular hairy, 7 − 12 mm long; equalling or longer than the subtending leaves; fruiting pedicel stiff, erect or horizontal. Calyx deeply 5-lobed, 3 − 5 mm long, linear or lanceolate, apex acute, sparsely glandular hairy when young. Corolla 6 − 7 mm long, white, occasionally with pale purple spots, tube 4.5 − 5 mm long; upper lip 1.5 mm long, slightly emarginated at the apex; lower lip distinctly 3-lobed, lobes rounded. Perfect stamens 2, filaments 1 mm long, glabrous; anthers 2-lobed, coherent below the upper lip. Staminodes 2, 1 mm long, linear, densely covered with yellowish stalked glands throughout and corolla tube below, distinctly spurred just below the apex. Ovary 1.3–1.5 × 0.6–0.8 mm, obliquely ellipsoid; disc annular, yellow; style 2.5–3 mm long; stigma 2-lamellate. Capsule 4–5 × 1.7–2 mm, ellipsoid or obliquely ellipsoid, obtuse to acute at apex, glabrous, equalling or slightly longer than persistent calyx. Seeds 0.3–0.4 × 0.1–0.2 mm, ellipsoid or slightly bent, golden yellowish, longitudinally ridged.

Phenology:─ Flowering and fruiting usually starts from July to December, sometimes up to March in some regions having permanently wet soil.

Distribution and habitat:─ The species is widely distributed in Argentina, Belize, Bolivia, Brazil, Canada, Chile, Colombia, Cuba, Dominican Republic, Ecuador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Puerto Rico, U.S.A. and Venezuela; introduced in Europe and East Asia ( Fischer et al. 2013). The present study shows that this taxon grows well in India ( Fig.2 ). It grows in the seasonal wet soils in open areas, soon after monsoon or close to water streams.

Specimens Examined:─ INDIA. Kerala: Idukki District , Chinnar Wildlife Sanctuary, 12 December 2012, M . G . Prasad & P . Sunojkumar 133431 ( CALI); Palghat District, Nelliyampathi , Karappara, 12 March 2012, C . N . Sunil, V . Abdul Jaleel & M . K . Ratheesh Narayanan 4904 ( MH!); Palghat , 15 January 1982, P . Manimohan 167 ( CALI!); Malappuram District , Kadalundi, 14 October 1985, K . C . Baby Jayalekha 7912 ( CALI!); Kadalundi , 15 August 1985, A . K . Valsa 7084 ( CALI!); Idukki District, Periyar Tiger Researve , Thannikkudy, 18 January 1995, Jomy Augustine & K . P . Rajesh 14585 ( CALI!) ; Andhra Pradesh: Chittoor District , Tirumala Hills, ± 1000 m, 7 July 1987, R . Charyulu 1568 ( MH!); West Godavari District, way to Kolleru lake , 24 January 1958, K . Subramanyan 5108 ( MH!); Gobanapalam , 25 January 1958, K . Subramanyan 5168 ( MH!); Hyderabad District, near Hussain Sagar Dam , 833 m, 28 April 1959, K . M . Sebastine 8045 ( MH!) ; Madhya Pradesh: Mandla District, Bank of river Narmada , 6 February 1961, J . Joseph 12205 ( MH!); Khari Reserve Forest , 26 November 1961, 675 m, J . Joseph 13419 ( MH!); Jubbulpore District, South of Forest Banglav , Kundwara, 472 m, 12 March 1962, K . M . Sebastine 13926 ( MH!) ; Orissa: Cuttack, CRRI field, 21 January 1986, 80 ft., K . P . Karthiayani 6316 ( CALI!) .

Figures

FIGURE 1. Lindernia dubia. A. Habit; B. Flower; C. Calyx; D. Corolla split opened; E. Gynoecium; F. Capsule; G. Seed.All drawn from M.G. Prasad & P. Sunojkumar133431 by M.G. Prasad.

FIGURE 2. Map of India showing the distribution of Lindernia dubia.