Prockiopsis razakamalalae G. E. Schatz, Lowry & Rakotovao

Schatz, George E. & Lowry, Porter P., 2013, Two more new species of Prockiopsis Baill. (Achariaceae) from Madagascar, Candollea 68 (2), pp. 277-283 : 281-283

Prockiopsis razakamalalae G. E. Schatz, Lowry & Rakotovao , spec. nova ( Fig. 3 ).

Typus: MADAGASCAR. Prov. Toliara: Anosy Region, Taolagnaro, Sarisambo, Ambohivola, forêt d’Ambatotstirongorongo , 25°05’00’’S 46°46’41’’E, 151 m, 22.II.2009, fl., Razakamalala & al. 4296 (holo-: MO-6440808 ! ; iso-: G [ G00341306 ]!, K!, P [ P05528356 ]!, TAN) .

Differing from all other species of Prockiopsis by possessing four small, linear petals, and by its narrowly elliptic leaves with a length to width ratio greater than 3:1.

Tree to 10 m tall. Young stems with sparse, minute appressed indumentum, soon glabrescent. Stipules 0.75 × 0.2 mm, narrowly triangular, glabrous, caducous. Leaves 3.1- 7.3 × 0.9-2.0 cm, narrowly elliptic, subcoriaceous, glabrous on both surfaces, base narrowly cuneate, margins with 5 to 8 crenulate-serrate teeth, apex narrowly acute, the acumen rounded, midrib flat above, raised below, glabrous, venation semicraspedodromous, 8 to 10 secondary veins per side, slightly raised on both surfaces, tertiary venation distinctly raised on both surfaces; petioles 3.5-6 mm, with sparse, minute appressed indument, glabrescent. Inflorescences axillary, pseudo-umbellate, 4- to 7-flowered, the peduncle at anthesis 2.5-3 mm long, 1 mm in diam., the rachis at anthesis 0-2.5 mm, peduncle and rachis with dense, light tan, appressed indument. Pedicels subtended by 3 overlapping, narrowly triangular, concave, minute bracts (2 inner and opposite, 1 outer), each 0.5- 1 0.5 mm, densely tan puberulent outside, glabrous inside, above which sits a distinct torus of dense trichomes surrounding the base of the pedicel; pedicels 16-25 mm, slender, to 0.5 mm in diam., with sparse to moderate, appressed tan indumentum. Calyx in bud 4.5-6 × 1.5-2 mm in diam., ellipsoid, base truncate, apex acute to rounded, entire, calyptriform and tearing irregularly, persistent through anthesis, thin and tissue-like, with sparse appressed tan indumentums outside, glabrous inside. Petals 4, equal, 4.5-6.5 × 0.7-1.1 mm, linear, glabrous outside, densely light ferruginous lanate inside, caducous. Stamens 9 to 12; filaments 1.5-4 mm long, sparsely light ferruginous lanate; anthers 2-2.8 × 0.5 mm. Ovary 2- 3 mm tall, 1.5-2 mm in diam., ellipsoid, nearly black “in seco”, with very sparse, appressed white trichomes, style 3-3.6 mm, stigma bifid or trifid, lobes 0.2 mm. Mature fruit not seen.

Etymology. – The species epithet honors our colleague Richard Razakamalala, whose sharp eyes have spotted many novelties that are contributing significantly to our ever-increasing knowledge of the Malagasy flora. Our colleague Charles Rakotovao, who collected the type specimen with Richard, first pointed out the possible novelty that we describe here and joins us as a co-author of this species.

Notes. – Prockiopsis razakamalalae is known only from a single gathering in the tiny fragments of the forêt d’Ambatotstirongorongo ca. 18 km west of Fort Dauphin in the transitional area between the humid and subarid bioclimatic zones of CORNET (1974; see SCHATZ, 2000). It can be easily distinguished from all other members of the genus by its narrowly elliptic, crenulate-serrate leaves with a length to width ratio of greater than 3:1, and by its four small, linear petals.

Conservation status. – The forêt d’Ambatotstirongorongo was briefly inventoried as a potential offset site for the QMM mining project, but currently is unprotected. Ongoing threats to the remaining tiny fragments of forest from human-set fires and cutting for fuelwood render the likelihood of persistence of P. razakamalalae extremely low over the next 3 generations (ca. 45 years). Thus, its risk of extinction can be assessed as “Critically Endangered” (CR A3c) following the IUCN Red List Categories and Criteria ( IUCN, 2012).

Figures

Fig. 3. – Holotype of Prockiopsis razakamalalae G. E. Schatz, Lowry & Rakotovao. [Razakamalala & al. 4296, MO] [© Missouri Botanical Garden, Saint Louis. Reproduced with permission]