Monopyle

Monopyle grandiflora Wiehler

Selbyana 5, t. 4a (1978)

Monopyle cf. maxonii C.V.Morton

Costa Rica, Alajuela, Valle Virgen, phot. A. Weber (1998)

Fig. 5. Flowers of selected Monopyle species; (a), (b) M. sp. (perhaps corresponding to "M. communis", one of the numerous inedited species of Keene (2013) and known from the Imabura district in Ecuador; (c) M. macrocarpa (s. lat.); (d) M. flava vel aff.; (e) M. sodiroana (in its trad. sense). All photos © G. Gerlach. Localities: (a), (b), (e) Ecuador, Prov. Imbabura, Lita to Altotambo, 734 m; (c) Ecuador, Prov. Napo, surroundings of Tena, 520 m; (d) Colombia, Dept. Valle del Cauca, along old road Buenaventura – Cali, 100-1000 m. Table from Weber, Weiller & Gerlach (in prep.).

Full name and orig. publication: Monopyle Moritz ex Benth., in Benth. & Hook.f., Gen. pl. 2: 997 (May 1876).

Etymology: From the Greek μόνος, monos = single, and πύλη, pylē = door, gate, opening. The name alludes to the capsular fruit which opens by a single (dorsal) slit.

Synonym: Scoliotheca Baill. (1888).

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

Description: Terrestrial, perennial herbs, with scaly rhizomes. Stem erect or decumbent, terete, slender, usually branched. Leaves opposite, anisophyllous, sometimes appearing alternate, joined across the stem in a stipular line; petiolate; lamina membranous, the base usually strongly oblique, often bullate or areolate above. Indumentum of hooked (uncinate) and/or stinging hairs. Flowers axillary pair-flowered cymes or in a terminal thyrse or raceme, then emerging from the axils of small bracts. Corolla somewhat zygomorphic; tube open-campanulate, base rounded, narrowed, or slightly saccate; limb 5-lobed, flaring, white or white with blue or yellow or speckled, with a yellow, marron or dark purple blotch in the throat. Stamens 4; filaments slender, curved inwardly, adnate to corolla base; anthers coherent, thecae divergent, connective thick. Nectary much reduced or lacking. Ovary inferior, narrowly turbinate; style thick; stigma stomatomorphic. Fruit a dry, linear-oblong capsule, topped by the persistent calyx, opening by a dorsal slit.

Chromosome number: 2n = 26.

Species number: Over 20.

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

Type species: Monopyle leucantha Moritz ex Benth. (see discussion in Keene 2013: 34).

Distribution: Along the western Cordillera from Peru to Guatemala.

Ecology: Terrestrial plants growing in wet, shady places in forests, lowland to montane forests.

Notes:
(1) Diagnostic features of the genus are the strongly anisophyllous leaves, the uncinate and/or stinging hairs (most species), the slightly zygomorphic and open-campanulate corolla, the lack of a nectary, and the completely inferior ovary. The characteristic fruit (a fleshy capsule splitting along its dorsal side) is shared with several taxa previously placed in Gloxinia.
(2) Keene (2013, unpubl.) indicated the number of species with around 100, based on the effects of autogamy and apomixis.
(3) While the flower shape is rather uniform, there is a considerable variety in colouration. A common pattern is white with bluish lobes and a yellow blotch at the base (putative osmophore), but there are also yellow and variously speckled corollas and the osmophore may be dark maroon, purple or disintegrated into individual markings.
(4) Regarding pollination, Wiehler (1976, 1983) believed that a "faint fragrance and the presence of an osmophore near the corolla base" would indicate andro-euglossophily (pollination by perfume-collecting male euglossine bees). "although this assumption has not yet been verified by field observation" (Wiehler 1983: 166).

Selected references: Wiehler, Selbyana 1(4): 374-404 (1976), notes; Wiehler, Selbyana 6: 1-219 (1983); Skog, Ann. Missouri Bot. Gard. 65: 942-946 (1979), reg. rev. (Panama); Roalson, Boggan, Skog, Zimmer, Taxon 54(2): 389-410 (2005a), molec. syst.; Roalson, Boggan, Skog, Selbyana 25(2): 225-238 (2005b), tax.; Keene et al., J. Bot. Res. Inst. Texas 5(2): 513-520 (2011), new spp. Ecuador; Keene, A reassessment of Monopyle (Gloxinieae: Gesneriaceae), Doctoral Thesis, Ohio State University (2013, unpubl.), numerous new spp. envisaged; Keene & Clark, Novon 23: 281–286 (2014), new spp. (Panama).

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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