Begonia sect. Microtuberosa Moonlight & Tebbitt, 2017

Peter Watson Moonlight, Carlos Reynel & Mark Tebbitt, 2017, Begonia elachista Moonlight & Tebbitt sp. nov., an enigmatic new species and a new section of Begonia (Begoniaceae) from Peru, European Journal of Taxonomy 281, pp. 1-13 : 4

Begonia sect. Microtuberosa Moonlight & Tebbitt sect. nov.

http://www.ipni.org/urn:lsid:ipni.org:names:77160200-1

Diagnosis

Begonia sect. Microtuberosa sect. nov. is most closely related to B. sect. Trachelocarpus and three species of B. sect. Gaerdtia . Both of these sections are endemic to eastern Brazil and differ markedly from sect. Microtuberosa sect. nov. in both their habit and Foral characteristics (see Table 1 ). However, all three sections share their Flaments fused at least at the base and B. sect. Microtuberosa sect. nov. further shares its androecium morphology with B. sect. Pereira and its lack of bracteoles with B. sect. Trachelocarpus . The majority of both Foral and vegetative characters are, however, markedly different among the three sections.

Begonia sect. Microtuberosa sect. nov. is readily identiFed as the only Neotropical section of Begonia with male Fowers with four or fewer stamens, and the combination of ovaries with two or three locules and entire placentas, and a tuberous habit.

Etymology

The name ‘ Microtuberosa ’ emphasises the diminutive and tuberous habit of the type species.

Type species

Begonia elachista Moonlight & Tebbitt sp. nov.

Description

Caulescent, tuberous herbs, perennial. Stems erect. Stipules persistent, entire. Leaves alternate, 2–4(–6), basiFxed, blade symmetrical or subsymmetrical, veins palmate. InForescence axillary, an asymmetric dichasial cyme, protandrous, bracts persistent. Male Fowers: with 2–4 free perianth segments; stamens 2 or 4, Flaments united into a column for more than half their length, anthers elliptic, dehiscing via lateral slits, connective not projecting. Female Fowers: bracteoles absent, with 2–3 free perianth segments; ovary and fruit with 2–3 wings, wings equal, 2–3-locular, placentas entire, bearing ovules on both surfaces; styles 2–3, free to base, biFd from about ⅔ their height, stigmatic papillae in a once spirally twisted band. Fruit a capsule. Seeds not examined.

Distribution

On a limestone outcrop in lowland Amazonian Peru to the east of the Chemillén Cordillera at an altitude of 430 m.