Four new species of Sapindaceae from the Guianas

Abstract Four new species of Sapindaceae from the Guianas, South America, are described, illustrated and contrasted with their putative, relatives: Matayba ayangannensis Acev.-Rodr. a small shrub from Mt. Ayanganna, Guyana; and Paullinia degranvillei Acev.-Rodr., Paullinia oldemanii Acev.-Rodr., and Paullinia prevostiana Acev.-Rodr., three species of lianas from French Guiana.


Introduction
While working on a treatment of Sapindaceae for the Flora of the Guianas (Acevedo-Rodríguez in prep.) four new species were discovered, one in Matayba, and three in Paullinia. In the Neotropics, Sapindaceae is a ubiquitous plant family with 37 genera and about 800 species. It is characterized by a woody habit (either trees, shrubs or lianas), compound alternate leaves, and flowers with petals usually bearing petaloid appendages on the adaxial surface. Fruit type and morphology are rather variable and often the basis for generic delimitation. Matayba is a Neotropical genus with about 50 species of trees or shrubs, 11 of which are found in the Guianas. Paullinia, also restricted to the Neotropics (except for P. pinnata, which is found also in Africa and Madagascar), has about 200 species of lianas or climbing shrubs. Paullinia is the largest genus of Sapindaceae in the Guianas, with 39 species occurring there. Description. Shrub to 2.5 m tall. Stems glabrous, striate. Leaves paripinnate; petiole plus rachis 2-6.5 cm long, slightly flattened adaxially, striate, puberulent; petiolules ca. 5 mm long, pulvinate at base; leaflets (4) 6, 2.5-4.5 × 1.2-2.3 cm, opposite or sub-opposite, obovate, oblanceolate or nearly elliptic, rigidly coriaceous, brittle, discolorous (abaxial surface drying brownish), adaxially glabrous, abaxially puberulent, especially along midvein, the base obtuse, symmetrical, the apex emarginate or less often rounded, the margins entire, slightly revolute; abaxially the midvein prominent, secondary and tertiary veins inconspicuous, reticulate. Thyrses 8-18 cm long, axillary, on distal portion of branches, paniculate, with ferruginous-pubescent and slightly angled axes. Flowers in simple dichasia; pedicels ca. 2 mm long, pubescent. Calyx brownish yellow, ferruginous-pubescent, ca. 1 mm long, the lobes 0.5-0.7 mm long, ovate; petals ca. 2 mm long, yellowish white, obovate, emarginate at apex, lanose mostly along margins; appendages 2, ca. 1 mm long, sericeous-tomentose, supra basal; disc glabrous, pulvinate; stamens 2-2.5 mm long, the filaments lanose on lower half; ovary tomentulose, the style subcapitate. Capsules not known.
Distribution and ecology. Known only from the type collection in Guyana, in low forest.
Distribution and ecology. Known only from French Guiana, from submontane forest.
Distribution and ecology. Known only from Guyana and French Guiana, in dense, humid forests, to be expected in Suriname. Discussion. Paullinia prevostiana seems to be closely related to P. tenuifolia Standl. as they share the following characters: Leaves pinnately 5-foliolate, terete stems with a single vascular cylinder; and cauliflorous inflorescence. Paullinia prevostiana differs however by its hispid leaves (vs. puberulent or glabrous), leaflets 5-18 cm long (vs. 3.5-11 cm) and its outer sepals much shorter than the inner ones (vs. nearly as long as the inner ones).
Etymology. The specific epithet honors Dr. Marie Françoise Prévost, plant ecologist at IRD who has collected numerous plant specimens from French Guiana, including the type of this species.