Phanera laotica Mattapha & Lanors.

Mattapha, S., Lanorsavanh, S., Lamxay, V. et al. Two new species of Phanera (Fabaceae: Cercidoideae) from Lao PDR. Kew Bull 76, 539–547 (2021). DOI: https://doi.org/10.1007/s12225-021-09964-1

Type

"Laos, Bolikhamxai province, Paksan distr., Xaysavang village, in older secondary forest with mixed deciduous and bamboo forests, 19°26'13.3""N 103°34'0.43""E, 161 m, 1 Dec. 2019, Lanorsavanh & Xaiyavong SL1764 (holotype HNL!; isotypes FOF!, KKU!)."

Morphology General Habit

Tendrilled woody climber; young branches ferruginous, densely hirsute; tendrils densely ferruginous tomentose

Morphology Leaves

Leaves simple, spirally arranged, coriaceous; blade oblong or ovate, 5 – 10.5 × 4.5 – 9.5 cm, base cordate, margin entire, ferruginous, apex bifid 2/3 of the blade with a filiform sinus 2 – 5 mm long, tips of lobes acute to almost rounded; upper surface pubescent, green, lower surface purple to reddish when young, turning green when mature, densely ferruginous tomentose, particularly along veins; secondary veins 10 – 12-nerved, raised on the underside, flat on the upper side; petioles 2.4 – 5 mm long, densely ferruginous tomentose; stipules lanceolate to oblong, 8 – 10 mm long, densely ferruginous tomentose outside, persistent

Morphology Reproductive morphology Inflorescences

Inflorescences racemose, erect, terminal, 22 – 45 cm long, with about 80 flowers, reddish pilose along axis; peduncles 3.5 – 5.2 cm long, reddish pilose; bracts lanceolate, 11 – 13 × 2 – 2.5 mm, outer surface brown pubescent, inner surface pubescent, caducous; bracteoles linear, 4 – 5 × 0.5 – 0.7 mm, surface similar to bracts, inserted below the middle of pedicels, caducous

Morphology Reproductive morphology Flowers Pedicel

Pedicels 1.7 – 2 cm long, brown pubescent

Morphology General Buds

Floral buds oblong, 0.8 – 10 × 5 – 6 mm, brown pubescent

Morphology Reproductive morphology Flowers Hypanthium

Hypanthium oblong, 10 – 12 × 6 – 7 mm, greenish to brown, brown pubescent, shallowly furrowed

Morphology Reproductive morphology Flowers Calyx

Calyx 5-lobed, splitting regularly at anthesis; lobes equal, oblong, reflexed, thick, 6 – 8 × 2 – 3 mm, green, apex acute, outer surface brown pubescent, inner surface white pubescent, persistent in fruit

Morphology Reproductive morphology Flowers Corolla

Corolla white; petals 5, subequal, limb elliptic, 8 – 11 × 4.5 – 7 mm, apex acute to cuspidate, margin slightly undulate and crisped, hairy, outer surface white tomentose, inner surface glabrous; claw less than 1 mm long; nerves 2 – 3

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens: fertile 3; filaments 8 – 9.5 mm long, glabrous; anthers oblong, 4.5 – 6.5 × 1.5 – 3.2 mm, dorsifixed, opening by longitudinal slits; staminodes 2, 2 – 2.5 mm long, anthers absent

Disc

Floral disc absent

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary oblong, densely white tomentose all over, shortly stipitate, c. 1 mm long; ovules 8 – 11; style 2 – 3 mm long, tomentose; stigma peltate, c. 0.5 mm diam. Pods oblong, flattened, 9 – 20 × 2.5 – 3.5 cm, green, sparely pilose, woody, dehiscent

Morphology Reproductive morphology Seeds

Seeds 9 – 11, orbicular, flattened, 1 – 1.6 × 1 – 1.5 cm, brown or black

Distribution

Only known from the type locality.

Ecology

The new species is known from the second-growth forest of deciduous trees and bamboo, situated in Bolikhamxai province, Paksan district, Xaysavang village, close to the Phou Khao Khouay National Protected Area. It grows on sandy soil mixed with gravel and stones. There are c. 30 individual plants in the type locality area as preliminarily observed.

Phenology

Flowering Nov. – Dec. and fruiting Dec. – Jan.

Etymology

The specific epithet refers to the country, Lao PDR, where the species was discovered and found as endemic.

Conservation

Preliminary conservation assessment. Critically Endangered CR B1ab(i,ii,iii,v) +2ab(i,ii,iii,v). Phaneralaotica is only known from the type locality, close to, and yet outside, a protected area, where about 30 individual mature plants were observed. It is at risk of extinction because of its small population size and Area of Occupancy (AOO), which is estimated to be smaller than 10 km2. The site is nearby an agricultural area subject to shifting agriculture and annual fires, therefore habitat degradation with consequent decline in the Extent of Occurrence (EOO) and number of mature individuals is a likely scenario for Phaneralaotica. Following the IUCN guidelines (IUCN 2012), we assign this new species a preliminary status as Critically Endangered (CR).