Popowia bachmaensis Ngoc, Tagane & Yahara, 2016

Ngoc, Nguyen Van, Tagane, Shuichiro, Binh, Hoang Thi, Toyama, Hironori, Okabe, Norikazu, Duy, Chinh Nguyen & Yahara, Tetsukazu, 2016, Popowia bachmaensis (Annonaceae), a new species from Bach Ma National Park, Central Vietnam, PhytoKeys 65, pp. 125-131 : 127-130

Popowia bachmaensis Ngoc, Tagane & Yahara sp. nov. Figs 1 , 2

Diagnosis.

Similar to Popowia pisocarpa (Blume) Endl. ex Walp., but distinguished from that species by having small habits (30-60 cm tall vs. 3-7 m tall in Popowia pisocarpa ), smaller leaves (4.6-10.8 cm × 2.0-5.6 cm vs. 5.5-14 cm × 2.5-7 cm in Popowia pisocarpa ), longer petioles (ca. 1.8-3 mm vs. 2-5 mm long) shorter flowering pedicels (2-3.5 vs. 4-7 mm long), longer sepals (ca. 3 mm vs. 2 mm long), longer inner petals (6 mm vs. 3 mm long), shorter carpels (2.1 mm vs. 10 mm long) (The measurements of Popowia pisocarpa derive from Sinclair 1955).

Type.

VIETNAM. Thua Thien Hue Province , Bach Ma National Park, in evergreen forest, 16°13'41.60"N, 107°51'09.35"E (DMS), alt. 485 m, 23 May 2015, with flowers and young fruits, Yahara T, Tagane S., Toyama H., Nguyen Ngoc, Nguyen Chinh, Okabe N. V2557 (holotype: KYO!; isotypes: BKF!, DLU!, FU!, the herbarium of Bach Ma National Park!) .

Description.

Shrubs, 30-60 cm tall. Young twigs hirtellous with yellowish brown hairs, glabrescent, blackish. Leaves alternate; petioles 1.8-3 mm long, hirtellous; blades elliptic, elliptic-obovate, obovate, (3.7-)4.6-10.8(-15) × 2.0-5.6 cm, length/width ratio 1.7-2.5(-3.2), base obtuse, usually asymmetric, apex acuminate, acumen up to 1.4 cm long, margin entire, ciliate, papery, dull greyish green to dull blackish brown adaxially, pale green, dull greyish green, or greyish brown abaxially, minutely granular, pubescent on both surfaces when young, glabrescent adaxially when old; midribs prominent abaxially, pubescent on both surfaces; secondary veins 7-11 pairs, arising at angle of 45-55 degrees from a midrib, prominent abaxially when dry, pubescent on both surfaces; tertiary veins faintly visible, scalariform-reticulate. Inflorescences extra-axillary or leave-opposed, fascicles of 1-3 flowers. Pedicels 2-3.5 mm long, hirtellous; bracts triangular, ca. 1 mm long, ca. 0.5 mm wide, brownish pubescent outside and margin, glabrous inside, bracteoles caducous. Sepals 3, broadly ovate, ca. 3 × 3 mm, pubescent outside, glabrous inside. Petals 6, white; outer petals ovate-triangular, ca. 2.7 × 1.5 mm, pubescent outside, glabrous inside; inner petals narrowly ovate-triangular, ca. 6 × 3.2 mm, pubescent on both surfaces except lower part of inside. Stamens 22 per flower, reverse truncated pyramid, ca. 1.1 × 0.8 mm, glabrous, the connective truncate, flat-topped or slightly concave, ca. 0.1-0.2 mm long; anthers ca. 0.7 mm long. Carpels 6 per flower, ca. 2.1 mm long; ovary ca. 1.1 mm long, glabrous; stigmas and pseudostyles reverse conical, ca. 1 × 0.7 mm. Immature fruiting pedicels ca. 3.5-4.0 mm long, pubescent with reddish brown hairs; monocarp three, globose, ca. 2.2 mm in diam., pubescent with short white hairs, hairs blackish brown when dried. Seeds one per monocarp, ca. 1.5 mm long, reddish brown, glabrous, furrowed when dried.

Distribution and habitat.

Vietnam (so far known only from its type locality).

Phenology.

Mature flowers and young fruits were collected in May.

Etymology.

The specific epithet ' bachmaensis ' is derived from the type locality, Mt. Bach Ma, Vietnam.

GeneBank accession No.

Yahara et al. V2557: LC090861 (rbcL), LC090860 (matK).

Conservation status.

Data Deficient (DD). During the botanical inventory carried out from 21 to 28 May 2015 from the foot to the top of Mt. Bach Ma, 15 individuals of Popowia bachmaensis were observed in all. They were found on the slopes of secondary hilly evergreen forest, at ca. 500 m elevation. Among them, only two individuals produced flowers, one produced fruits, and the others are just saplings. According to the population size observed, this species can be qualified as Critically Endangered (CR) ( IUCN 2012). However, only a limited area of the forest in the vicinity of the type locality was surveyed, and further field surveys are needed to determine the actual population size within Bach Ma National Park. The forest of the type locality was slightly disturbed in the past, but it is now well-protected from human activities.

Figures

Figure 1. Popowia bachmaensis, sp. nov. a Holotype (KYO) b habit c flower d pedicel and sepals e sepals f section of flower g inner petal h fruit on branch i dried fruit j seed k carpel l, m stamens. Materials from Yahara et al. V 2557 (KYO). Scale bars: d-g, i-m = 1 mm.

Figure 2. Illustration of Popowia bachmaensis, sp. nov. a Leafy twig b Flower c Pedicel and sepals d Fruit e Inner petal f Carpel and g Stamen. Materials all from Yahara et al. V 2557 (FU). Drawn by Ngoc & Binh.