Begonia octopetala subsp. ovatiformis Irmsch.

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 : 169-170

36.2 Begonia octopetala subsp. ovatiformis Irmsch.

Fig. 52B

Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 76: 75 ( Irmscher 1953).

– Type: PERU – [Huánuco Region: Prov. Huánuco] • Estacion near Muña ; ca 1980 m a.s.l.; [9°40′ S, 75°49′ W]; 20 May–1 Jun. 1923; J.E. Macbride 4143; holotype: F [ V0042326F , photo K].

Brako & Zarucchi (1993: 194); León & Monsalve (2006: 167); Tebbitt (2015: 484).

Etymology

Irmscher (1953) distinguished this variety from other members of the species primarily by its ovate leaf blades. The epithet refers to this characteristic.

Specimen examined

PERU – Huánuco Region: Prov. Huánuco • Clefts of rocks near Muña ; [9°40′ S, 75°49′ W]; 2745– 3050 m a.s.l.; May 1863, coll. unknown 185; K .

Description

Acaulescent, rhizomatous herb, to 45 cm high. Rhizome ellipsoid, ca 3.5 × 2 cm, with 1 growing point. Stipules persistent, triangular, ca 9 × 9 mm, apex obtuse, opaque, brown, glabrous, margin entire, aciliate to sparsely ciliate. Leaves 1–3, alternate, basifixed; petiole 14–17 cm long, colour unknown, lanate; blade subsymmetric, triangular in outline, to 21 × 15.5 cm, succulent, apex obtuse, base cordate, basal lobes not overlapping or overlapping, sinus to 50 mm deep, margin with 0–5 short, crenate lobes on both sides of the lamina, dentate, ciliate, upper surface green, pilose, lower surface pale green, glabrous to sparsely pilose, veins palmate but with 1 primary vein, 5–6 veined from the base, with 1–3 secondary veins on the larger side, 1–3 on the smaller side. Inflorescences 1–3, bisexual, axillary, erect, a dichasial or monochasial cyme, with 1–3 branches, bearing up to 3 staminate flowers and 2 pistillate flowers, protandrous; peduncle to 45 cm long, red, sparsely to densely lanate, bracts persistent, ovate to lanceolate, 5–11 × 2–8 mm, opaque, white, green, or red, glabrous to lanate, apex acute to obtuse, margin entire, aciliate. Staminate flowers: pedicels to 3 cm long, sparsely to densely lanate; tepals 6, spreading, oblanceolate to obovate, 17–22 × 7–17 mm, apex rounded, white to pink, glabrous, margin entire, aciliate; stamens 50–75, spreading, yellow, filaments 2–3 mm long, free, anthers obovoid, ca 1 × 0.5 mm, dehiscing via lateral slits, connectives extended to ca 0.2 mm, symmetrically basifixed. Pistillate flowers: pedicels to 9 cm long; bracteoles unknown or lacking; tepals ca 7, subequal, late deciduous in fruit, spreading, obovate, 7–17 × 7–13 mm, apex rounded to truncate, white to pink, glabrous on the inner surface, sparsely to densely lanate on the outer surface, margin entire, aciliate; ovary body ovoid to broadly obovoid, 6–13 × 5–13 mm, white to pink, densely lanate, unequally 3-winged, the largest rectangular, ascending, 7–13 × 7–25 mm, the smallest a semi-circular ridge, 0.5–1 mm wide; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, free, 3–4 mm long,> 5 times-divided, stigmatic papillae in a spirally twisted band. Fruiting pedicel to 9 cm long. Fruit body obovoid, to 13 × 13 mm, drying brown, wings same shape as in ovary, the largest expanding to 13 × 50 mm, the smallest not expanding.

Proposed conservation assessment

Previously assessed by León & Monsalve (2006) as Data Deficient (DD). Known from a single population but not collected for <100 years, though this area is poorly collected. We have been unable to visit this locality so assess B. octopetala var. ovatiformis as Data Deficient (DD).

Notes

The taxonomic status of this subspecies is unclear. It is known from two specimens, which share some characteristics with B. octopetala and others with B. aequatorialis Irmsch. The types of these two species differ substantially: the type of B. octopetala has broadly ovate leaves that lack a distinct apex; subsymmetric inflorescences; staminate flowers with> 6 tepals;> 1.5 cm broad tepals on the staminate flowers; and ascending largest fruit wings. In contrast, the type of B. aequatorialis has much smaller, deltoid leaves with a distinct apex; asymmetric inflorescences; staminate flowers with 6 tepals; <1.5 cm broad tepals on the staminate flowers; and non-ascending largest fruit wings. Irmscher’s concept of B. octopetala subsp. ovatiformis is intermediate between these two species. It differs from the type of B. octopetala in having deltoid leaf laminae with a clear apex; six tepals on the staminate flower; and ascending largest fruit wings but differs from the type of B. aequatorialis in having subsymmetric inflorescences and broader tepals on the staminate flowers. The boundaries between the three taxa have become blurred due to the recent collection of several collections of B. octopetala from the Andean cordillera. These specimens tend to have smaller, more triangular shaped leaves (e.g., P.W. Moonlight & A. Daza 106) and narrower tepals on the staminate flower (e.g., P.W. Moonlight & A. Daza 229) than the type of B. octopetala but remain distinct from the type of B. octopetala subsp. ovatiformis in their non-ascending fruit wings.

Mark Tebbitt is currently undertaking a full taxonomic revision of B. sect. Eupetalum (Tebbitt in prep.) following his recent revision of the closely related B. sect. Australes ( Tebbitt 2020). We suspect the boundaries of these species may change as a result of this revision but maintain B. octopetala subsp. ovatiformis as a distinct taxon in this treatment.

Identification notes

Distinct from most specimens of B. octopetala in its leaf laminae, which are deltoid in outline (vs circular to rarely deltoid), and its staminate flowers, which have 6 (vs 6–11 tepals). The only character that can distinguish this subspecies reliably is its ascending (vs non-ascending) fruit and ovary wings.

Distribution and ecology

Endemic to Peru and Huánuco Region ( Fig. 52B ). Known from 1980–3050 m a.s.l. in elevation in middle and upper montane forest. Like the type subspecies, B. octopetala var. ovatiformis is tuberous and likely dies down to its tuber in the dry season.

Figures

Fig. 52. Distribution of the octopetala group of Begonia sect. Eupetalum (Lindl.) A.DC. in Peru and surrounding countries. A. B. anemoniflora Irmsch. (red) and B. tumbezensis Irmsch. (blue). B. B. octopetala L.Hér. subsp. octopetala (red) and B. octopetala subsp. ovatiformis Irmsch. (blue). C. B. pleiopetala A.DC. (red) and B. pseudopleiopetala Tebbitt (blue). D. B. polypetala A.DC. (red). Black lines indicate country borders, grey lines indicate major administrative divisions, blue lines indicate rivers, and shading indicates elevation.