Episcia

Full name and orig. publication: Episcia Mart., Nov. gen. sp. pl. 3: 39 (Jan.-June 1829).

Etymology: From the Greek επι, epi = on, upon; and σκια, skia = shadow, in reference to the shady habitat of the plants.

Synonyms: Centrosolenia Benth. (1846), Episcia Mart. sect. Centrosolenia (Benth.) Benth. (1876), Episcia Mart. sect. Episcia subsect. Centrosolenia (Benth.) Leeuwenb., p.p. (1958), Episcia Mart. sect. Episcia subsect. Trematanthera Leeuwenb. (1958), Cyrtodeira Hanst. (1854).

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

Description: Stoloniferous, terrestrial or saxicolous herbs. Stem creeping, rooting at nodes, dichasially branched by the regular production of stolons. Leaves opposite, the lower pair with axillary stolons, upper pairs crowded, bearing the flowers in their axil; petiole short; lamina without hypodermis; upper surface dark green or with various patterns of variegation, lower surface often colored. Cymes of 1-6 axillary flowers, peduncles slender. Sepals free or shortly connate, upper sepal forced back around the corolla spur, green or colored. Corolla white, yellow, blue, purple or red, inserted horizontally in the calyx, zygomorphic salverform to campanulate, conspicuously spurred, contracted above the spur and at the throat, rarely ventricose, limb oblique, lobes spreading, rounded, entire, their margin minutely toothed or fimbriate. Stamens 4, didynamous, included; filaments nearly straight, inserted at corolla base, after anthesis depressed or coiling; anthers coherent in pairs or in a square, becoming free, dehiscing by a longitudinal slit. Nectary a single large, dorsal gland. Ovary superior; stigma stomatomorphic, bilobed or capitate. Fruit an ovoid bivalved fleshy capsule.

Chromosome number: 2n = 18.

Species number: 10.

Species names (given only in case of few species).

Type species: Episcia reptans Mart.

Distribution: From tropical South America to Nicaragua and the Guianas.

Ecology: In tropical forests, in damp places, slopes, banks or rocks, usually at low elevations, partly forming large colonies.

Notes:
(1) Around 70 species have been described in Episcia, but the genus was much reduced in size by Wiehler (1978). The presently 10 species can be referred to two sections: (a) sect. Episcia (7 spp.), and (b) sect. Trematanthera (Leeuwenb.) Feuillet (3 spp.; Feuillet 2008).
(2) Though the corolla form is fairly uniform in Episcia as well in the allied genus Alsobia, ("episcioid corolla"), the colouration and the presence/absence of a fimbriate limb suggests pollination by various animal groups: euglossine bees (e.g., Episcia fimbriata, with whitish and slightly fimbriate corolla lobes ), birds (E. cupreata, corolla bright red), and (probably) butterflies (E. lilacina, corolla long-tubed, mouth constricted).

Selected references: Wiehler, Selbyana 5: 25-28 (1978), emend. & rev.; Skog, Ann. Missouri Bot. Gard. 65: 918-923 (1979), reg. rev. (incl. Alsobia) (Panama); Feuillet & Steyermark, Fl. Venezuel. Guayana 5 (1999), reg. rev.; Skog, Monogr. Syst. Bot. Missouri Bot. Gard. 85: 1114-1128 (2001), reg. rev. (Nicaragua); Feuillet, J. Bot. Res. Inst. Texas 2(1): 275-280 (2008), new sect., new spp.

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

Page content and update responsibility/contact: Laurence E. Skog.
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