Leea trifoliata M. A. Lawson, Hook. f.

Athalappil, Amrutha, Pradeep, Ayilliath Kuttiyeri, Wen, Jun & Krishna, Nikhil, 2025, Resolving the taxonomy of Leea trifoliata (Leeaceae, Vitales): Reinstatement and typification, PhytoKeys 266, pp. 281-295 : 281-295

Leea trifoliata M. A. Lawson, Hook. f. (Ed), Fl. Brit. India 1 (3): 666. 1875.

Figs 1 , 2

Leea trifoliata M. A. Lawson, Hook. f. (Ed), Fl. Brit. India 1 (3): 666. 1875; C. B. Clarke, Trimen’s J. Bot. 19: 163. 1881; Kanjilal & Das, Fl. Assam 1 (2): 305. 1936. Type: INDIA. Assam, s. d., Jenkins & c. s. n. ( lectotype, designated by Ridsdale 1974, pg. 88: K [ K 000736385]; isolectotype: K [ K 000323729]).

Description.

Perennial weak herb, 0.8–1 (– 2.5) m high; roots non-tuberous. Stems erect or wiry, jointed, warted, glabrous; internodes furrowed, green; nodes swollen; pearl glands globose, white. Leaves alternate, trifoliate or 1 - pinnate with two rudimentary pairs of leaves at base; petioles 7–21 mm long, slightly bulged, sheathing the stem, hairy at base, green. Petiolar stipules narrowly winged, expanding the full length of the petiole, 2–2.5 cm long; stipular scars triangular; rachises 1–4 cm long, channeled and slightly winged on upper surface, hispid on margin, green. Leaflets opposite, elliptic oblong or obovate, distal leaflets lamina: 5.5–13 × 2.7–7.5 cm, lateral leaflets lamina: 4.5–12.5 × 2–6 cm, one row of stiff hairs in between nerves on upper surface, mature leaves green on upper surface and pale green on lower, base cuneate, margins serrate, apex cuspidate caudate, abruptly acuminate; petiolules: central 1–2.5 cm long, lateral 0.2–0.7 cm long, channeled and winged on upper surface, green; secondary veins 7–16 pairs, 3 - nerved at base, strigose on lower surface, vein raised on abaxial side. Inflorescences terminal or leaf-opposed, compound cyme, up to 4 cm long, axis hispid. Bracts 1.8–2.7 mm long, lanceolate-linear, pubescent. Calyx campanulate, c. 3.5 mm long, 5 lobed, each lobe c. 1–1.5 mm long, apex acute; corolla lobes 5, 2.7–2.8 × 1.1–1.3 mm, slightly hooded at apex, margin entire. Floral disc 1.1–1.5 mm long. Ovary 4–6 locular. Fruits noted as black in Lawson (1875).

Flowering and fruiting.

June – December.

Habitat.

This species mostly grows on roadsides and forest margins. They grow along with Adiantum sp. ( Pteridaceae ), Impatiens minor (DC.) Bennet , Impatiens balsamina L. (both Balsaminaceae ) and some grasses.

Distribution.

Bhutan, India ( Assam & Arunachal Pradesh). Fig. 3 .

Specimens examined.

Bhutan. s. d., Booth s. n. ( K 000323730 ) . India. • Arunachal Pradesh: Mishmi hills , s. d., Griffith 1344 ( K 004252755 , P 02342863 ) ; • East Kameng district, Pakke Wildlife Sanctuary , 25 Apr 2012, B. B. T. Tham 35028 ( ARUN) ; • Kamle district, Raga , 27°47'59.4"N, 94°04'29.7"E, 16 Aug 2018, Amrutha 159851 ( CALI) ; • Assam: s. d., Masters s. n ( K 004252752 ) ; • Cachar district, Bhuban Hills , Oct 1978, 74142 ( ASSAM) ; • Cachar , June 1874, R. L. Keenen s. n. ( K 004252761 ) ; • Darrang district, Aka Hills , s. d., N. L. Bohr 17378 ( ASSAM) ; • Dibrugarh district, Dibru Reserve, eastern part , 20 Oct 1960, G. Panigrahi 21564 ( ASSAM) ; • Golaghat district, s. loc, 300 ft, May 1891, Dr. King’s collectors s. n. ( US 01151426 , K 004252756 , P 02342865 , L 0744660 ) ; • Jorhat district, Gibbon Sanctuary, Camp- 2 , 12 June 2010, Ranjit Daimary 122699 ( ASSAM) ; • Ibid., Camp- 4, 26 Feb 2011, Ranjit Daimary 121691 ( ASSAM) ; • Kamarup district, Moyang Residence , 09 Apr 1915, U. Kanjilal 5449 ( ASSAM) ; Kamarup Metropolitan district, Guwahati , April 1902, A. C. Chatterjee ( P 02342864 , LY 0106862 , MPU 703118 ) ; • Karbi Anglong district, • Garampani Wildlife Sanctuary , 24 Nov 1975, P. K. Hajra 65058 ( ASSAM) ; Kaliani , 18 June 1963, D. B. Deb 35116 ( ASSAM) ; • Nagaon district, Laopani , 28 Aug 1978, P. Chakraborty 78984 ( ASSAM) ; • Sonitpur district, Batasipur , 13 May 1947, M. M. Srinivasan 22253 ( ASSAM) ; • Kanchanjuri, Kazhiranga , 12 Aug 1973, P. K. Hajra 52836 ( ASSAM) ; • Tinsukia district, Margherita Forest , 22 June 1938, G. K. Duka 17010 ( ASSAM) .

Conservation status.

Leea trifoliata is restricted to two northeastern Indian states, Assam and Arunachal Pradesh, and one location in Bhutan. This species prefers to grow in open areas adjoining evergreen forests. The Extent of Occurrence ( EOO) is calculated to be 114,777 km 2, and the Area of Occupancy ( AOO) is 84 km 2. Considering its large Extent of Occurrence, this species does not fall into any threat category. Despite this, the Area of Occupancy is small, and each population has fewer than five mature individuals. Due to its narrow range of distributions and small AOO, this species could be categorized at present as Endangered ( EN), B 2 b (ii, iii) according to the IUCN Standards and Petitions Committee (2022).

Notes.

In the protologue, Lawson (1875) described the anthers as distinct, and the fruits were black.

Ridsdale (1974) typified the name L. trifoliata by selecting the Jenkins & c. material from Assam as the lectotype. We were able to trace two sheets of Jenkins & c. from the Kew herbarium ( K 000736385 & K 000323729 ). However, Ridsdale has attached a slip to the sheet with barcode K 000323729 stating that it is the lectotype. Hence, the other sheet ( K 000736385 ) becomes the isolectotype.

Figures

Figure 1. Leea trifoliata M. A. Lawson: A, D. Habit; B. Adaxial surface of leaflet showing trichomes; C. Abaxial surface of leaflet showing trichome on nerves; E, F. Petiolar stipules; G. Rachis showing wings; H. Stem; I – K. Leaves; L – N. Inflorescences with bracts; Fl ower Bud.

Figure 2. A twig of Leea trifoliata M. A. Lawson (Drawn by Amrutha A. from Amrutha 159851).

Figure 3. Distribution of Leea trifoliata M. A. Lawson in northeastern India and Bhutan (drawn using QGIS version 3.24. 3).