Nautilocalyx

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Nautilocalyx

Description

Terrestrial or rarely epiphytic, caulescent, decumbent to erect herbs or low shrubs, occasionally tuberous. Stems rarely branched. Leaves opposite, equal or unequal in a pair, venation pinnate, foliar nectaries absent. Flowers axillary, 1-15 in pedunculate or epedunculate, fasciculate, or cymose inflorescences; bracteoles usually present; pedicellate. Calyx lobes free; corolla white to yellow, red or purple, usually with spots or lines of purple, tubular, broadened laterally; stamens included, filaments basally connate, anthers apically coherent in 2 pairs, dehiscing by longitudinal slits, thecae parallel or divergent; staminode minute to small; disc a single dorsal gland or 2 opposite glands; ovary superior, stigma stomatomorphic to 2-lobed. Fruit a fleshy, loculicidally dehiscent, white or colored capsule, 2-valved, valves opening slightly or to 180°.

Distribution

Amazonian Brazil: present C America: present Guianas: present Lesser Antilles: present Northern America: Southern America:, Colombia (Colombiapresent); Panamá (Panamápresent); Peru (Perupresent); Venezuela (Venezuelapresent) northern S America: present
More than 50 species found in the Lesser Antilles, C America from Mexico to Panama, and throughout northern S America from Peru to Colombia, to Venezuela and the Guianas, and Amazonian Brazil; 11 species in the Guianas.

Cytology

Chromosome number n = 9 (18) (Skog 1984).

Notes

The generic name derives from a supposed similarity between the shape of the bracts of the type species and a nautilus shell (fide Planchon).
The presence of N. villosus (Kunth & Bouché) Sprague had been suggested in French Guiana (Leeuwenberg, 1958). This species seems to be restricted to western Venezuela and neighbouring parts of Colombia. All specimens from the Guianas identified as N. villosus can be placed in N. fasciculatus, N. pallidus, or N. pictus.
A few specimens document the presence of N. melittifolius (L.) Wiehler (mentioned as Episcia melittifolia (L.) Mart. in Leeuwenberg 1958, 1984) as a house and garden ornamental plant in French Guiana. It is not known to escape cultivation and we include it only in the key.