Christopheria

Full name and orig. publication: Christopheria J.F.Smith & J.L.Clark, Syst. Bot. 38(2):453 (2013).

Etymology: "The name is derived from the first and last names, respectively, of Christopher Davidson and Sharon Christoph who have provided both logistical and intellectual support to the first author [J.F.Smith], including the trip to French Guiana where leaf material for this species was collected" (Smith & Clark 2013: 456).

Synonyms: –

Infrafamilial position: Gesnerioideae-Gesnerieae-Columneinae (Weber et al. 2013) (Weber et al. 2013).

Description (of genus and only species, from Smith & Clark 2013: 453): Creeping, stoloniferous herb with pale yellow corolla. — Terrestrial stoloniferous herb with two stolons per node. Stems decumbent, terete, 5–7 mm diam, internodes ca. 1–2.5 cm long, pilose, nodes with adventitious roots. Leaves opposite, equal to subequal; petiole hirsute, 1–8 cm long; blade bullate, elliptic-ovate, 5–20 3–15 cm, papery when dry, apex obtuse to acute, base rounded to subcordate, margin crenate-serrate, adaxial surface green, pilose with impressed veins, adaxial surface tinged with purple to entirely purple, sparsely pilose to glabrous with prominent veins, lateral veins 4–8 per side. Inflorescences axillary, pedunculate, flowers few to many in cymes; peduncle purplish, sparsely pilose to glabrous, 1.5–5 cm long; bracts resembling sepals but smaller in size, 4–8 1.2–2 mm; pedicels 3–12 mm long, sparsely pilose or glabrous. Calyx pale green, lobes nearly free, sparsely pubescent on both surfaces, four sepals subequal, obovate, 10–12 5–8 mm with 2–5 teeth near the obtuse apex, gradually narrowed toward the base and spreading, dorsal lobe smaller, 9–11 2–2.5 mm and curved around the dorsal nectary gland, margin ciliate. Corolla posture oblique relative to calyx, yellow with 4–5 red spots ventrally in throat, 21–26 mm long, 2.5–3 mm diam at the base and 7–10 mm at the throat, not constricted, exterior hirsute at the throat, becoming glabrous at the base, interior partially pubescent with glandular hairs in the throat, limb 17–20 mm wide, lobes subequal, suborbicular, 5 6–7 mm, rounded, margin entire, spreading. Androecium of 4 fertile stamens included in the throat; filaments glabrous, curling after anthesis, connate at base and adnate to the corolla; anthers coherent in pairs, suborbicular, 1.2 1.2 mm, staminode small, glabrous, 0.5 0.1–0.2 mm. Ovary hirsute except glabrous at the base, ovoid, laterally compressed, 3–4 2–3 mm, style glabrous, stigma capitate. Nectary a single dorsal gland. Fruit a bivalved capsule, subglobose, laterally compressed, 10 6mm, acute or obtuse, pubescent, color uncertain on specimens. Seeds ellipsoid, ca. 1.0 x 0.3 mm, obliquely striate, light to dark brown.

Chromosome numbers: Unknown.

Type and only species: Christopheria xantha (Leeuwenb.) J.F.Smith & J.L.Clark (= Basionym: Episcia xantha Leeuwenb.)

Distribution: French Guiana, Guyana.

Ecology: Growing in forests, on old logs or epiphytically on dead trunks, between 50-500m altitude.

Notes:
(1) The genus Christopheria emanated from a molecular-phylogenetic study of Paradrymona and allies by Smith & Clark (2013).
(2) As shown by Mora & Clark (2016), the genus is part of the so-called "Guiana Shield clade" within Generieae-Columneinae, an alliance of six genera (all monotypic except Rhoogeton with 2 species) endemic to the Guiana Shield in northeastern South America (for details see 'Notes' under Lembocarpus). Despite its former inclusion in Episcia (a neotropical genus also producing two stolons per node, but yellow flowers absent) it is neither closely related to that genus nor to other neotropical Gesneriaceae with stolons.

Selected references: Smith & Clark, Syst. Bot. 38(2):451-463 (2013); Mora & Clark, Syst. Bot. 41(1): 82-104 (2016), molec. syst. Paradrymonia and allies.

Tax. details, cytology, and bibliography: Gesneriaceae Resource Centre (GRC). Royal Botanic Garden Edinburgh.

Page content and update responsibility/contact: John L. Clark.
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