Saurauia homotricha (Actinidiaceae), a New Species from Honduras and Nicaragua

Abstract

Saurauia homotricha, a new species from montane forests of western Honduras and Nicaragua, is described and illustrated. It is placed in the Central American series Gymnogynae Buscalioni and is most similar to Saurauia rubiformis Vatke, from which it differs most markedly in the type, length, and distribution of trichomes on the leaves and the abaxial surface of the sepals. The genus Saurauia consists of approximately 300 species from the Neotropics (excluding the Antilles) and tropical Asia. Twenty-five species have been recognized for Mexico and Central America; 22 are treated in Hunter's (1966) revision of the Mexican and Central American species, with 2 more Mexican species described by Keller and Breedlove (1981) and 1 more from Honduras described by Soejarto (1985). An additional species of Saurauia from Honduras and Nicaragua was recognized during preparation of a treatment of the Actinidiaceae for the Flora de Nicaragua and is here described. The pubescence terminology employed is that described and illustrated in Hunter's revision. Saurauia homotricha A. Pool, sp. nov. TYPE: Nicaragua. Nueva Segovia: Rfo Achuapa, al sur del Cerro Mogot6n, 1500 m, 12 June 1975 (buds and flowers), Atwood & Neill 16 (holotype, MO; isotype, HNMN?). Figure 1. Species nova Saurauiae rubiformi Vatke similis, sed ab ea foliis supra inter venulas setulosis trichomatibus 1-1.5 mm longis infra inter venulas hirsutis atque stellato-pilosis, sepalorum partibus in alabastro expositis plumulososetulosis trichomatibus 1.75-2 mm longis differt. Small tree, ca. 5 m tall, the young branches densely covered with shaggy-hirsute to shaggy-setose trichomes; trichomes to 2 mm long, shaggy mainly at base, golden to rusty-brown, mixed with minute, appressed-stellate trichomes. Leaves alternate, aggregated at tips of branches. Petioles 1.53.5 cm long, terete, indumentum as on young branches. Leaf blades oblanceolate, 19-28 cm long, 7-11 cm wide, short-acuminate at apex, cuneate to rounded at base, serrulate, with 16-29 pairs of secondary veins; tertiary veins more prominent on abaxial surface than higher order venation; adaxial surface abundantly to sparingly covered with setose trichomes 1-1.5 mm long; abaxial surface abundantly covered with a mixture of hirsute and stellate trichomes with long spreading arms, with primary and secondary veins densely covered by shaggy-setose trichomes. Inflorescence a narrow, axillary thyrse with 9-20 flowers, 3.5-14 cm long, peduncle 1.5-6 cm long, indumentum as on young branches; flowers actinomorphic, 14-18 mm diam.; sepal aestivation quincuncial, sepals elliptic to oblanceolate, 7-9 mm long, 4-4.5 mm wide, obtuse at apex, non-ciliolate, adaxial surfaces densely covered with minute, appressed-stellate trichomes, abaxial surface of outer two sepals densely covered with 1.75-2 mm long, shaggy-setose trichomes throughout, abaxial surface of imbricate sepal with exterior half (half exposed in bud) densely covered with 1.75-2 mm long, shaggy-setose trichomes and interior half densely covered with minute, appressed-stellate trichomes, abaxial surface of two inner sepals medially with dense 1.75-2 mm long, shaggy-setose trichomes and laterally and marginally densely covered with minute, appressed-stellate trichomes; petals 5, connate at base, oblong, 6-7 mm long, 3-5 mm wide, obtuse at apex, white; stamens 20-26, filaments adnate to base of corolla, 1.5-2 mm long, pubescent at base, trichomes filiform, anthers 2-2.5 mm long; ovary globose, glabrous, 5-locular, styles 5, 4-5 mm long. Fruit a berry, globose, 5-sulcate, ca. 5 mm diam., glabrous. Soejarto (1969) suggested that many species of Saurauia have dimorphic flowers: one form functionally staminate with short styles and high pollen fertility and the other form functionally pistillate with long styles and low pollen fertility. A shortstyled form of Saurauia homotricha is not currently known. Hunter (1966) recognized four series in Saurauia for Mexico and Central America: Gymnogynae Buscalioni, Gynotrichae Buscalioni, Oreophilae Buscalioni, and Laevigatae Buscalioni. Saurauia homotricha belongs to the series Gymnogynae, which (as emended by Hunter) is characterized by leaves NovoN 8: 280-282. 1998. This content downloaded from 157.55.39.59 on Sat, 15 Oct 2016 04:18:12 UTC All use subject to http://about.jstor.org/terms Volume 8, Number 3 Pool 281 1998 Saurauia homotricha