17. Echites P. Browne, Civ. Nat. Hist. Jamaica. 182. 1756.
[Greek echis, viper, and ites, of the nature of, alluding to twining habit and deleterious quality]
David E. Lemke
Allotoonia J. F. Morales & J. K. Williams
Woody vines; latex milky. Stems trailing, unarmed, glabrous [eglandular-pubescent]. Leaves persistent, opposite, petiolate, stipular colleters interpetiolar [absent]; laminar colleters absent. Inflorescences axillary, terminal, or subterminal, cymose, pedunculate. Flowers: calycine colleters present; corolla white or pale yellow [pinkish white, yellow-orange, orange], salverform, aestivation dextrorse; corolline corona absent; androecium and gynoecium not united into a gynostegium; stamens inserted at or below middle of corolla tube; anthers connivent, adherent to stigma, connectives enlarged, 2-lobed, locules 4; pollen free, not massed into pollinia, translators absent; nectaries 5, distinct [connate and forming disc], alternating with stamens. Fruits follicles, usually paired, erect or deflexed, brown, slender, terete or moniliform, surface striate, glabrous. Seeds ovate, flattened, not winged, beaked, comose, not arillate. x = 6.
Species 9 or 10 (1 in the flora): Florida, Mexico, West Indies, Central America, South America (Colombia).
Echites was one of the first neotropical genera of Apocynaceae to be described. Because it was originally broadly defined, it was progressively expanded by later authors to include hundreds of species. Work by R. E. Woodson Jr. (1936) was instrumental in redefining Echites as a small group of species segregated into two subgenera, the remaining taxa being reduced to synonymy or transferred to other genera such as Angadenia, Mandevilla, Mesechites Müller Arg., Odontadenia Bentham, Pentalinon, Prestonia R. Brown, Rhabdadenia, and Trachelospermum, a treatment largely followed by J. F. Morales (1997). A cladistic analysis of Echites based on morphological characters (J. K. Williams 2004b) suggested that Echites, as circumscribed by both Woodson and Morales, was polyphyletic but that the species belonging to the two subgenera formed monophyletic clades. Consequently, Morales and Williams proposed the genus Allotoonia to include the five species of Echites subg. Pseudechites Woodson. However, a more recent phylogenetic analysis based on a combination of morphological and molecular characters (T. Livshultz et al. 2007) does not support the recognition of Allotoonia, and Echites is presently recognized as a genus of nine or ten species.
SELECTED REFERENCES Morales, J. F. 1997. A reevaluation of Echites and Prestonia sect. Coalitae (Apocynaceae). Brittonia 49: 328–336. Williams, J. K. 2004b. Polyphyly of the genus Echites (Apocynaceae: Apocynoideae: Echiteae): Evidence based on a morphological cladistic analysis. Sida 21: 117–131.
