Begonia serratistipula Moonlight, 2023

Moonlight, Peter. W., Jara-Muñoz, Orlando A., Purvis, David A., Delves, Jay, Allen, Josh P. & Reynel, Carlos, 2023, The genus Begonia (Begoniaceae) in Peru, European Journal of Taxonomy 881, pp. 1-334 : 95-96

17. Begonia serratistipula Moonlight sp. nov.

urn:lsid:ipni.org:names:77323290-1

Fig. 24C

Diagnosis

Most similar to B. cyathophora but differing in its stipules, the bottom third of which have a lacerate margin (vs stipules with entire margins); its first pair of bracts free (vs fused into an obconicular cyathium); its staminate flowers with 6–10 stamens (vs ca 25); and its pistillate flowers with 2 bracteoles (vs lacking bracteoles).

Etymology

The species is named for its stipules, which have characteristic serrated margins.

Type

PERU – Amazonas Region: Prov. Chachapoyas • Dist. Leimebamba, camino a Monumentos Historicós de Pajatén ; 6°34’23.76”S, 77°38’28.92”W; 1792 m a.s.l.; 29 Aug. 2004; V. Quipuscoa S., M. Vílchez T. & W. Meza E. 3170; holotype: HUT [ HUT no. 44128] .

Description

Caulescent herb, to 80 cm high. Stem erect, branching; internodes to 6.5 cm long, to 3 mm thick, succulent, green, glabrous. Stipules persistent, lanceolate to oblanceolate, 28–33 × 9–15 mm, apex acuminate, translucent, pale green flushed pink, glabrous, margin lacerate for the basal third, entire for the remainder, ciliate for the basal third then aciliate. Leaves> 5, alternate, basifixed; petiole 3–4.5 cm long, red, glabrous; blade asymmetrical, ovate, to 12 × 6.5 cm, succulent, apex acuminate, base obliquely cordate, basal lobes overlapping, sinus to 20 mm deep, margin irregularly double dentate, ciliate, upper surface dark green, glabrous, lower surface green flushed deep red, glabrous, veins palmate but with 1 major vein, 7–9 veined from the base, with 2–3 secondary veins on the larger side, 1–2 secondary veins on the smaller side. Inflorescences 1 or more per stem, bisexual, axillary, erect, cymose, with 3 branches, bearing up to 32 staminate flowers and 16 pistillate flowers, protandrous; peduncle to 10 cm long, dark red, glabrous, bracts deciduous, the first pair broadly obovate, ca 25 × 25 mm, translucent, pink, glabrous, apex truncate, margin entire to lacerate at the apex, ciliate, subsequent bracts lanceolate, 12–15 × 2–4 mm. Staminate flowers: pedicels to 10 mm long, glabrous; tepals 2, spreading, broadly ovate, 7–8 × 7–8 mm, apex obtuse to rounded, pink, glabrous, margin entire, aciliate; stamens 6–10, projecting, pale yellow, filaments 0.5–1 mm long, free, anthers elliptic, 1–1.5 × 0.2 mm long, dehiscing via lateral slits, connectives extending to 0.2 mm, symmetrically basifixed. Pistillate flowers: pedicels to 17 mm long; bracteoles 2, positioned directly beneath the ovary, ellipsoid, ca 5 × 1.5 mm, apex acute, translucent, pink, glabrous, margin lacerate, ciliate; 2 equal tepals or 3 unequal tepals, deciduous in fruit, spreading, the largest two ovate to broadly ovate, 13–15 × 6–10 mm, apex obtuse to rounded, pink, glabrous, margin entire, aciliate, the smallest if present ovate, ca 12 × 5 mm, apex obtuse, pink, glabrous, margin entire, aciliate; ovary body ovoid, ca 8 × 5 mm, pink, glabrous, unequally 3-winged, wings triangular, largest ca 14 × 14 mm, smallest ca 10 × 3–4 mm; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, free, 3–4 mm long, once-divided, stigmatic papillae in a spirally twisted band. Fruiting pedicel to 20 mm long. Fruit body ovoid, to 11 × 7 mm, drying dark red then brown, wings same shape as in ovary, the largest expanding to 14 × 18 mm, the smallest expanding to 12 × 6 mm.

Proposed conservation assessment

Known only from a single population but nothing is known about the size of the species’ population or trends in the species population. The type locality is very remote but is part of the drainage of the río Huayabamba. There has been significant, recent deforestation in this drainage in Amazonas Region, including within 2 km of the type locality. We assess B. serratistipula sp. nov. as Vulnerable (VU D2).

Identification notes

Begonia serratistipula sp. nov. is best distinguished from all other members of B. sect. Cyathocnemis by its stipules, which are entire towards the apex but uniquely lacerate and long ciliate towards the base. It may be confused with B. cyathophora but can further be distinguished by its ciliate (vs aciliate) leaf margins, or B. obtecticaulis , but differs in its bifid (vs multifid) styles and its stipules that do not clasp the stem.

Distribution and ecology

Endemic to Peru and Amazonas Region ( Fig. 24C ). Known from a single population in middle montane forest at an elevation of 1792 m a.s.l. Note that the type locality is a minor archaeological site known as Pajatén in Leimebamba District and not the famous site known as Gran Pajatén in Huicungo District, Mariscal Cáceres Province, San Martín Region but normally accessed from Chachapoyas Province in Amazonas Region ( Church & Álvarez 2004). The ecology of this species is unknown, but it likely occurs at the edge of montane forest patches in common with most species in the section.

Figures

Fig. 24. Distribution ofBegonia sect.Cyathocnemis (Klotzsch)A.DC. in Peru and surrounding countries. A. B. amoeboides Moonlight (red) andB. imbrexiformis Moonlight sp. nov. (blue).B. B. bracteosaA.DC. (red) and B. longinqua Moonlight (blue). C. B. cyathophora Poepp. & Endl. (red), B. serratistipula Moonlight sp. nov. (blue) and C. vargasii Moonlight sp. nov. (green). D. B. lamolina Moonlight (red), B. lophoptera Rolfe (blue) and B. obtecticaulis Irmsch. (green). Black lines indicate country borders, grey lines indicate major administrative divisions, blue lines indicate rivers, and shading indicates elevation.