Begonia section Pilderia (Klotzsch) A.DC., 1859

Moonlight, P. W. & Jara-Muñoz, A., 2017, A revision and recircumscription of Begonia Section Pilderia including one new species, Phytotaxa 307 (1), pp. 1-22 : 5

Begonia section Pilderia (Klotzsch) A.DC.

Ann. Sci. Nat., Bot. 4, 11: 141 (1859).— Pilderia Klotzsch, Ber. Berkanntm. Verh. Konigl. Presuss. Akad. Wiss. Berlin 1854: 127 (1854). Lectotype species (designated J.J. Swart 1960): Pilderia urticaeafolia Klotzsch ex Klotzsch = Begonia buddleiifolia A.DC. (heterotypic synonym).

Plants caulescent, with rhizomatous or upright stems, monoecious, with an indumentum of glandular and non-glandular hairs; stem repent, rhizomatous, succulent or thin and wirey rooting adventitiously at least at the lower nodes; stipules persistent. Leaves, alternate, basifixed; lamina asymmetric at least at the base, straight or transverse, lanceolate to ovate, acuspidate or cuspidate; inflorescence axillary, terminal, repent or erect, thyrsoid, lower lateral branches thyrsoid or all lateral branches cymose, lateral cymes branching 0–5 times, protandrous; bracts of thyrsoid lateral branches leaflike, the remainder bract-like, deciduous to persistent. Male flowers: tepals 2 or 4, in unequal pairs, free, white to red; androecium symmetric; stamens united along the length of a column, anthers dehiscing through lateral slits. Female flowers: bracteoles 2 or 3, deciduous to persistent; tepals 5, deciduous to persistent, subequal; ovary body globose, 3-locular, unequally 3-winged; placentae axile, simple or bilamellate, ovuliferous all over; styles 3, bifid, branches spirally twisted.

Distribution:— Colombia, Ecuador, Guyana, Perú, Trinidad and Tobago, Venezuela.

Taxonomic comments:— Begonia section Pilderia appears from morphological and molecular evidence to be most closely related to B. rossmanniae A.DC. in the monotypic B. sect. Rossmannia (Klotzsch) A.DC. The two sections share a number of key characters, including semi-persistent to persistent bracteoles and a bisexual, asymmetric, terminal, thyrsoid inflorescence. The phylogeny in this paper confirms this relationship. The two sections differ in their indumenta: B. rossmanniae is entirely glabrous whereas all species in B. sect. Pilderia have indumenta of both glandular and non-glandular hairs. B. sect. Pilderia further differs in its female flowers with five petals ( B. rossmanniae has two).

Notes:— The online version of Index Nominum Genoricum (ING) states that Pilderia urticaefolia was designated as the Lectotype of Pilderia by J.J. Swart on the 1 st of March 1960, with the ING card reference 10693. We have been unable to locate this reference, but follow this designation.