Lagenandra wayambae Madola, K.Yakandawala, D.Yakandawala & Karunaratne, 2021

Madola, Indrakheela, Yakandawala, Kapila, Yakandawala, Deepthi & Karunaratne, Senani, 2021, Lagenandra wayambae (Araceae), a new endemic species from a freshwater swamp forest of Sri Lanka, Phytotaxa 489 (2), pp. 216-222 : 217-220

Lagenandra wayambae Madola, K.Yakandawala, D.Yakandawala & Karunaratne sp. nov. ( Figs. 2–4)

Leaves of L. wayambae are similar in shape and length with that of L. thwaitesii but differs by having narrower leaves, absence of a silver line in the margin and leaf blades that are placed mostly at more or less right angle to the upright petiole. Similarly, the spathe of L. wayambae resembles that of L. lancifolia but possess large number of warts outside and a yellow spadix.

Type: — SRI LANKA, Western Province, Kalutara District, Walauwewaththa Wathurana freshwater swamp forest Bulathsinhala , 30 m asl, Collected 20 th February 2020, Madola, K . Yakandawala and D. Yakandawala L169 (holotype PDA!, isotypes PDA!, K!) .

Evergreen small herb with creeping to erect rhizome ca. 0.4–0.6 cm in diam. Cataphylls ca. 2–6 cm. Petiole ca. 7–17 cm long (longer when covered with sand), ca. 0.1–0.3 cm wide, sheath ca. 1.2–1.7 cm long, unequal. Leaf blades green to dark green, blades are placed mostly at more or less right angle to the upright petiole. Blade mostly linear lanceolate or rarely linear ovate, 6–10 times longer than broad, apex acute, long tapered, base acute or obtuse, margin entire, blade ca. 8–15 × 1–2 cm; midrib visible on both surfaces and prominent on the lower surface. Peduncle ca. 0.2–0.5 cm long and occasionally even up to 6.6 cm long when covered with sand, 0.1–0.7 cm width, terete. Spathe dark maroon warty outside especially on the limb, ca. 1.0– 4.5 cm long, kettle ca. 0.4–0.9 × 0.5–0.9 cm, dark maroon with smooth longitudinal striations inside; limb ca. 0.4–3.2 cm, opening by a slight twist dark maroon and horizontally irregularly ribbed inside; tail ca. 0.2–0.4 cm. Spadix ca. 0.4–0.6 cm long; pistillate flower zone ca. 0.1–0.2 x 0.3–0.5 cm; sterile zone ca. 0.1 cm long (whitish pink); staminate flower zone ca. 0.1–0.3 x 0.2–0.4 cm (yellow); appendix ca. 0.1 cm long (dark maroon). Pistils ca. 15, up-right with rather short protuberances below the subdome-shaped stigma. Style clearly visible. Staminate flowers ca. 70. Infructescence up to 11 cm long, oblate with few fruitlets, peduncle 0.2–6.6 cm long, fleshy capsule up to 10, with warty out-growths. Seeds 1–2, size ca. 0.4–0.6 x 0.3–0.4 cm and longitudinally ridged.

Distribution, phenology and conservation status: —To date the distribution of L. wayambae appears to be restricted to one locality in Sri Lanka, the fresh water swamp forest in Walauwewaththa Wathurana, Bulathsinghala at an elevation of approximately 20–30 m asl. We encountered two populations, that occurs less than 500 m apart, one with very few individuals (less than 10 plants) within the freshwater swamp forest while the larger healthy population occurring in close proximity outside the protected area. The larger population contains about 60 mature plants, and at present, we are not aware of any other locality in Sri Lanka where this species persists.

Lagenandra wayambae flowers in December and January-April. Fruiting February–July. The open inflorescence persists for 3–4 days.

The calculated AOO accounted to 4 km 2 while we were unable to calculate the EOO due to the presence of only one data point. Therefore, the EOO was also taken as equal to AOO. Considering the facts that L. wayambae being restricted to one locality in Sri Lanka, and the number of healthy individuals in the population within the freshwater swamp forest secure very few individuals and the larger healthy population that occur outside the protected area is subjected to anthropogenic activities, the two populations could be considered as under threat. Further, the population placed outside the protected area is flooded during the rainy season, where the plants remain inundated for few days. In addition, the recent anthropogenic involvements in the close vicinity have instigated muddy waters entering the habitat and sand to deposit after the drainage of the muddy water. This sand permanently covers the plants fully affecting their healthy growth as well as complete disappearing of smaller individuals. Following the present IUCN (2019) guidelines; based on geographic range, with only 4 km 2 of EOO and AOO, this species qualifies for Critically Endangered category (CR) under the thresholds for both B1 and B2. Considering the anthropogenic activities outside protected area, number of locations is considered as 1 (a). Further, considering the subcategories, the large healthy population of L. wayambae located outside the protected area exhibited a continuing decline in the EOO (bi) and AOO (bii) and exhibited in the quality of the habitat (biii) as well as the number of mature individuals (bv). Considering all these facts, L. wayambae qualifies for Critically Endangered category under Criterion B1ab (ii,iii,v) + B2ab (ii,iii,v).

Habitat: —The Walauwewaththa Wathurana fresh water swamp forest is a unique ecosystem which is presently under protection of the Central Environment Authority of Sri Lanka ( CEA, 2009), and is the only freshwater swamp forest recorded up to date in the country. Freshwater swamp forests are identified as a major sub category among Palustrine (Inland Wetlands) under the Ramsar Classification System for Wetland Types ( Ramsar Convention Secretariat, 2016). Located in the Kalu Ganga river basin in the southwestern part of Sri Lanka, along the Batapotte ela, a tributary of the Kalu Ganga (IUCN and CEA, 2006), the water level of the area reaches few feet during the flooding season, which continue up to two or three weeks. The plants occur in the shady, ground layer of the swamp forest inundated in sandy soils with silt. Rare and threatened endemic plant species recorded in this ecosystem include Stemnoporus mooni Thwaites (1992: 129), Mesua stylosa (Thwaites) Kostermans (1969: 430) Areca concina Thwaites (1864: 328) and Diospyros quaesita Thwaites (1864:179) ( Gunatilleke et al. 2008). With the recognition of L. wayambae , the significance of this site further increases raising the number of point endemics to three, together with S. mooni and M. stylosa .

Eponymy: —The new species is named after the Wayamba University of Sri Lanka.