Trivalvaria recurva Chaowasku & D.M.Johnson

Johnson, David M., Chaowasku, Tanawat, Murray, Nancy A. & Chalermglin, Piya, 2021, Three new species of Trivalvaria (Annonaceae) from Thailand, with a key to the Thai species, Phytotaxa 489 (1), pp. 79-86: 80-82

publication ID 10.11646/phytotaxa.489.1.6


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scientific name

Trivalvaria recurva Chaowasku & D.M.Johnson

sp. nov.

Trivalvaria recurva Chaowasku & D.M.Johnson   , sp. nov. ( Figs. 1C–E View FIGURE 1 , 2C,F View FIGURE 2 )

Type:— THAILAND. Kanchanaburi: Phuye, Thong Pha Phum District , ca. 350 m, 8 August 2010 (flower), Nakorn-Thiemchan NTC 13 (holotype: BKF!)   .

This new species most resembles T. casseabriae Y.H.Tan, S.S.Zhou & B.Yang   in Yang et al. (2018: 5) in its small flowers with short white petals, but the petals are only ca. 3 mm long and strongly recurved versus 6–10 mm long and spreading, and the leaves are elliptic to oblanceolate with a maximum width of 6.8 cm versus lanceolate to oblong with a maximum width of 5.5 cm ( Table 1).

Shrubs with twigs persistently short-pubescent. Leaves elliptic to oblanceolate, 13.8–17.2  4.8–6.8 cm, base cuneate, apex sharply acuminate, the acumen 5–16 mm long, glabrous except for hairs along midrib above and below, secondary veins eucamptodromous, 7–10 per side, arcuate; petiole 5.5–9.0 mm long. Inflorescences internodal, 1–2-flowered, peduncles 1.5–3.0 mm long, pedicels ca. 1.2 mm long, bearing 1 minute bract; buds with petals separated and erect early in development, exceeded by androecium. Flowers bisexual or staminate. Sepals semicircular, ca. 2 mm long, obtuse, sericeous. Petals white, recurved at anthesis, glabrate on both surfaces, outer petals ovate, ca. 3  2.7 mm, acute, inner petals oblong, ca. 3.0  2.0 mm, rounded. Stamens 50–100, forming a globose boss ca. 3.0 mm [fluidpreserved] in diameter, clavate, ca. 1.7 mm long, anther connective apex truncate, glabrous to sparsely pubescent. Carpels 4–7, ovaries not examined, stigmas exceeding the tops of the stamens, irregular, pubescent. Receptacle not visible. Fruit of ca. 9 monocarps borne on a short pedicel. Monocarps red in vivo, oblong, acute at the apex.

Distribution and Ecology:— Known only from the type collection from Kanchanaburi Province in southwestern Thailand, where the plant occurs in evergreen forest at ca. 350 m.

Phenology:— Flowering August.

Etymology:— Named for the petals recurved at anthesis.

Vernacular names:— Ma khao dok   lek (มะขาวดอกเล็ก) (Kanchanaburi), sakao phrai (สกาวไพร) (General).

Conservation status:— Trivalvaria recurva   occurs within the boundaries of a national park, an area not yet widely surveyed for the species. At present, the status of the species should be considered data deficient.

Notes:— Trivalvaria recurva   is distinctive among Thai species in having short petals that are separated at the tips from an early stage of development and recurved at anthesis. A photograph of the fruit ( Fig. 2F View FIGURE 2 , and Chalermglin (2001: 131) under Polyalthia Blume (1830: 68))   shows that the monocarps are red when mature, nearly sessile, oblong and slightly acute at the apex. Trivalvaria recurva   was collected from an area of Kanchanaburi Province where other narrowly distributed Annonaceae   species occur, for example Pseuduvaria phuyensis ( Saunders, Su & Chalermglin, 2004: 42) Y.C.F.Su & R.M.K.Saunders   in Su et al. (2010: 37). Trivalvaria ochroleuca   is the only other Trivalvaria species   known from this area and can be distinguished from T. recurva   by its shorter blunt leaf acumen 3–8 mm long, inflorescences sub-opposite the leaves and greater numbers of stamens and carpels.


National Park, Wildlife and Plant Conservation Department