Dictyanthus species

Pío-León, Juan Fernando & Alvarado-Cárdenas, Leonardo O., 2023, Another remarkable new species of Dictyanthus (Apocynaceae, Asclepiadoideae, Asclepiadeae, Gonolobinae) with a long stylar head from Mexico, Phytotaxa 632 (2), pp. 175-183 : 182

Identification key for Dictyanthus species with convex stylar appendage

1. Corolla less than 2 cm in diameter, lobes reticulate to fully purple; gynostegial corona lobes rhombic...................... D. nichongus

- Corolla greater than 2.5 cm in diameter, lobes reticulate; gynostegial corona lobes linear-spatulate or spatulate ............................2

2. Corolla lobes patent, gynostegial corona lobes spatulate and exceeding corolla tube; apex of gynostegium conspicuously apiculate, greater than 3 mm long, and exserted from corolla tube................................................................................................. D. unicornus

- Corolla lobes revolute, gynostegial corona lobes linear-spatulate, shorter than or equal to corolla tube in length; apex of gynostegium convex or apiculate, less than 2 mm long, included in corolla tube...................................................................................................3

3. Corolla tube conspicuously reticulate, distribution exclusively east of the Isthmus of Tehuantepec ................................................4

- Corolla tube with horizontal or vertical lines, distribution not exclusive to the east of the Isthmus of Tehuantepec........................5

4. Apex of gynostegium 1–2 mm long, gynostegial corona lobes with one prominent tooth each, trichomes on corolla lobes restricted to reticulations ........................................................................................................................................................... D. ceratopetalus

- Apex of gynostegium less than 1 mm long, gynostegial corona lobes without teeth, trichomes on corolla lobes evenly distributed ............................................................................................................................................................................................. D. eximius

5. Corolla tube with horizontal lines ...................................................................................................................................... D. tigrinus

- Corolla tube with vertical lines...........................................................................................................................................................6

6. Plants erect to occasionally climbing, inflorescence reduced to a single flower, gynostegial corona lobes with two teeth at half their length, apex of gynostegium convex ...................................................................................................................... D. macvaughianus

- Climbing plants, inflorescence 1–3 flowers, gynostegial crown lobes without teeth at half their length, apex of gynostegium apiculate..............................................................................................................................................................................................7

7. Gynostegial corona lobes reaching throat of corolla tube, calyx and outer surface of corolla glabrous, corolla tube with ca. 5 lines between each corona lobe...................................................................................................................................................... D. lautus

- Gynostegial corona lobes below corolla tube, calyx and outer surface of corolla not glabrous, corolla tube with more than 5 lines between each corona lobe.................................................................................................................................................... D. pavonii