Costularia species

Henriette, Elvina, Larridon, Isabel, Morel, Charles, Goetghebeur, Paul & Senterre, Bruno, 2015, Revision of the genus Costularia (Cyperaceae: Schoeneae) for the flora of the Seychelles, including the rediscovery and resurrection of a rare endemic species, Phytotaxa 231 (1), pp. 31-41 : 33

Key to Costularia species on the Seychelles

1. Leaves tristichous, with a well defined midrib; inflorescences not contracted, with the branches arcuate downwards; rachilla elongate and sinuose..................................................................................................................................................................... C. hornei

- Leaves distichous, without midrib; inforescences contracted, with the branches held close to the main axis; rachilla short and straight ............................................................................................................................................................................. C. xipholepis