Key to Capsular-Fruited Genera of Dialypetalantheae in the Neotropics
(Note: some genera are diagnosed by a combination of flower and fruit characters)
1. Inflorescences axillary.
2. Corolla lobes thinly imbricated in bud; capsules septicidal; seeds suborbicular, 0.3--1 mm long..... Chimarrhis Jacq.
2'. Corolla lobes convolute in bud; capsules loculidal through the apical portion; seeds cylindrical to navicular, 22--26 mm long..... Lintersemina H. Mend., Á Celis, & M. Gonzalez
1'. Inflorescences terminal and sometimes also in axils of uppermost leaves.
3. Flowers bisexual and protogynous..... Warszewiczia Klotzsch
3'. Flowers bisexual and protandrous, or unisexual on dioecious plants.
4. Scandent or clambering plants; stipules interpetiolar and rounded; plants dioecious with unisexual flowers.....Dioicodendron Steyerm.
4'. Erect shrubs and trees; stipules rounded to acute, variously interpetiolar, intrapetiolar, or calyptrate; plants with bisexual flowers.
5. Stipules fused at base into a tube, with their upper parts splitting into two intrapetiolar segments or two bilobed interpetiolar segments; capsules loculicidal.
6. Trichomes of mixed form, with some simple and some stellate or dendritic; corolla divided to base into secondarily free lobes or petals; stamens 16--25..... Dialypetalanthus Kuhlm.
6'. Trichomes all simple; corolla fused in basal portion into a tube; stamens 5.
7. Leaves without domatia or with domatia present only along costa; corollas with the lobes half or more as long as the tube and widely spreading at anthesis; capsules dehiscing in a short apical slit through the beak portion..... Elaeagia Wedd.
7'. Leaves with regularly developed domatia along costa and usually also in axils of tertiary veins; corollas with the lobes a third as long as the tube or shorter and only shortly spreading at anthesis; capsules dehiscing from top through main body of the fruit into two valves..... Holtonia Standl.
5'. Stipules free or shortly fused at the base with their upper parts interpetiolar and unlobed, or fused completely into a calyptrate cap that splits along one side or irregularly; capsules loculicidal or septicidal.
8. Capsules septicidal. 9. Capsules subglobose; seeds angled to discoid, sometimes with thin margins but not evidently winged..... Bathysa C. Presl
9'. Capsules ellipsoid to obovoid or subglobose; seeds fusiform to ellipsoid and flattened, with marginal wing.
10. Calycophylls absent; corolla lobes in bud convolute and overlapping for 1/3 or more of their width, at anthesis becoming emarginate to bilobed at tip..... Ferdinandusa Pohl
10'. Calycophylls absent or present; corolla lobes in bud imbricated or thinly convolute and overlapping for at most 1/10th of their width, at anthesis acute to obtuse at tip.
11. Stipules interpetiolar and free, or fused completely into a calyptrate cap; corolla white to cream, internally pubescent in upper part of tube; anthers basifixed; calyx limb persistent on capsule..... Calycophyllum DC. (including Semaphyllanthe L. Andersson)
11'. Stipules interpetiolar and free or shortly fused at base; corolla pink, lilac, or purple, internally glabrous throughout or pubescent in lower part of tube; anthers dorsifixed; calyx limb deciduous from capsule..... Wittmackanthus Kuntze
8'. Capsules loculicidal. 12. Capsules dehiscent along side margins, with valves remaining fused at top; corolla lobes reduplicate-valvate in bud..... Macrocnemum P. Browne
12'. Capsules dehiscent from apex into two valves or only through apical disk portion; corolla lobes imbricated, convolute, valvate, or perhaps open in bud.
13. Corolla red to purple, with lobes valvate in bud; Greater Antilles..... Picardaea Urb.
13'. Corolla white, cream, or green and sometimes marked with dull purple, with lobes imbricated, convolute, or perhaps open in bud; Mexico, Central America, and South America.
14. Stipules interpetiolar; corolla lobes imbricated or open in bud; capsule subglobose; seeds flattened and elliptic, with well developed wing.
15. Internal tissues of stems and fruits not oxidizing purple; capsules 0.5--1 cm in diameter; trees of inundated forest along rivers in the Amazon basin..... Parachimarrhis Ducke
15'. Internal tissues of stems and fruits oxidixing purple; at least some capsules 1.1--9 cm in diameter; trees and shrubs of various habitats from Mexico to southern Brazil..... Simira Aubl.
14' Stipules interpetiolar or fused into a calyptrate cap; corolla lobes convolute in bud; capsule subglobose to ellipsoid or obovoid; seeds angled to or flattened and fusiform, unwinged or with irregularly developed narrow wings.
16. Stipules interpetiolar..... Macbrideina Standl.
16'. Stipules fused into a calyptrate cap..... Schizocalyx Wedd.