Lagenandra peradeniyae var. speciosa Madola, D.Yakandawala & K.Yakandawala, 2022

Madola, Indrakheela, Yakandawala, Deepthi & Yakandawala, Kapila, 2022, A new Lagenandra species with two varieties from the Wet Zone of Sri Lanka, Phytotaxa 567 (2), pp. 110-126 : 120-125

Lagenandra peradeniyae var. speciosa Madola, D.Yakandawala & K.Yakandawala var. nov. ( Figs. 4 , 5 , 6 (B), 7 (B1 and B2), 10 and 11)

Lagenandra peradeniyae var. speciosa differs from the type variety by lance-ovate leaves and the silver colour appearing towards either side of the mid rib of the leaf lamina, rounded base and spathe light green/yellow mixed with maroon/purple.

Type:— SRI LANKA, Western Province, Colombo District, in the Indikada Mukalana Forest Reserve of Sri Lanka , 50 m asl. Collected 08th of March 2021, Madola, D. Yakandawala & K. Yakandawala L171 (holotype PDA!, isotypes PDA!, K!) .

Leaf blades light green with the silver colour appearing towards the either side of the mid rib, lance-ovate, apex acuminate, base rounded, margin entire, blade ca. 8.6–15.4 × 2.9–5.2 cm. Peduncle ca. 7.8–17.3 cm long. Spathe light green/yellow mixed with maroon/purple, 7.9–12.8 cm long. Pistils ca. 28–32. Staminate flowers ca. 48–52.

Etymology:— The new variety name refers to its striking habit.

Distribution, phenology and conservation status:— To date, the distribution of L. peradeniyae together with its varieties is restricted to only one locality in Sri Lanka, along a main stream and a streamlet originating from the Idikada Mokalana Forest Reserve, which joins the Wak-oya stream. The population is scattered and spread over a stretch of about 200 m. The population consists of about 30 mature individuals ( L. peradeniyae var. peradeniyae , 20 mature individuals and L. peradeniyae var. speciosa , 10 mature individuals) with 10–15 young individuals.

The Indikada Mukalana Forest Reserve was declared as a forest reserve initially in 2008 (Gazette no. 1572/9 of the Forest Ordinance on October 21, 2008) but soon after it was de-gazetted through Gazette no. 1585/14 on January 21, 2009 ( Chamikara 2011). However, in 2012, the forest has regained its position as a Forest Reserve (Gazette no. 1759/2 of the Forest Ordinance on May 21, 2012). Indikada Mukalana Forest Reserve is the second largest tropical lowland rainforest in the Colombo District, Sri Lanka with an extent of 572 ha and is situated in the Western Province of the country. It contributes to the conservation of a number of plants and animals including many endemics ( Chamikara 2011, Dias and Udayakantha 2016, Wijerathna et al. 2017).

Lagenandra peradeniyae , with two varieties both equally attractive, could be considered as one of the most attractive Lagenandra species described to date in the world. Of the other described Lagenandra species, L. thwaitesii with a silver margin on the leaves has gained popularity as an ornamental plant in the ornamental aquatic plant industry. It is being sold around the world via e-commerce (e.g. Premiumbuces 2021, Aquasabi 2022). The plants are still extracted from the wild and therefore are severely threatened in their natural habitats. Further, the recently described L. srilankensis also possess a silver margin. However, the silver margin in L. srilankensis appears faint against the light green colour of the leaf blade oppose to the dark green leaves of L. thwaitesii ( Madola et al. 2021b) . The leaves of L. peradeniyae exhibit potential characteristics for it to become a popular ornamental plant in the industry. This could be attributed to the variegated leaves, with silver patches in L. peradeniyae var. peradeniyae and green with the silver colour appearing towards either side of the mid rib in L. peradeniyae var. speciosa . In addition to the leaf characters, another feature of interest is the orientation of the spathe that stands well above the leaves that are aligned more or less parallel to the substrate. This feature highlights the inflorescence from the foliage. Therefore, both the spathe and the leaves are of ornamental significance. Consequently, with the discloser of the species, the plant would be exposed to many risks, especially illegal collections, where a situation the authorities need to address immediately.

Lagenandra peradeniyae flowers from February-August, fruiting from April-September. The open inflorescence persists for 6–8 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. peradeniyae being restricted to only one locality in the country, and the number of healthy individuals in the subpopulations are restricted to less than 30 mature individuals, could be considered as threatened. Due to the ornamental potential, illegal extractions are likely. Following the present IUCN guidelines (2019); based on geographic range, this species qualifies for Critically Endangered category (CR) under the thresholds for both B1 and B2, with number of locations is considered as 1 (a). Further, the subpopulations exhibited a continuing decline in the quality of habitat (iii) and number of mature individuals (v). When considering all these facts, L. peradeniyae qualifies for CR category under Criterion B1ab (iii, v) + B2ab (iii, v). Evaluation under the Criterion C; Small population size and decline, where the number of mature individuals been <250, and with an observed, estimated, projected, or inferred continuing decline in the number of mature individuals in each subpopulation C2 (i), L. peradeniyae qualifies for the CR category under Criterion C2. Therefore, the conservation status of L. peradeniyae based on IUCN (2019) is determined; B1ab (iii, v) + B2ab (iii, v) and C2 (a) (i).

Habitat:— The plants inhabit shady stream banks which are not directly interrelated with the water and in the crevices of the stones in the cascading systems of streams and streamlets of a low country evergreen rain forest.

As L. peradeniyae is the only Sri Lankan species which has a spathe that stands well above the leaves that are aligned more or less parallel to the substrate giving way to the spathe, it can key out as a first lead in the key presented in Madola et al. 2021b.

Figures

FIGURE 4. Distribution of Lagenandra peradeniyae; Lagenandra peradeniyae var. peradeniyae and L. peradeniyae var. speciosa, in the Wet Zone of Sri Lanka.

FIGURE 5. Habitat of Lagenandra peradeniyae, either A. Between the crevices of the stones in running water or B. On the banks of the stream.

FIGURE 6. Habit of Lagenandra peradeniyae; A. Lagenandra peradeniyae var. peradeniyae and B. L. peradeniyae var. speciosa.