Cephalanthus

Abstract: The circumscription of the tribe Naucleeae has been under debate for a long time. This is the first study to test if the previous circumscriptions are supported as monophyletic. Parsimony analyses of the rbcL sequence data of Rubiaceae, followed by separate and combined analyses of the ITS, rbcL, and morphological data were performed in attempt to propose a new tribal delimitation for Naucleeae. Results did not support any of the previous delimitations of Naucleeae. All favoured a broader circumscription, which includes not only all members of Naucleeae sensu Ridsdale, but also Cephalanthus, Hallea, Mitragyna, and Uncaria, formerly placed in Naucleeae, Corynanthe and Pausinystalia. Naucleeae sensu Ridsdale were shown to be monophyletic without support in the morphology- and combined ITS-rbcL-morphology-based trees. The tribe Coptosapelteae sensu Andersson & Persson appeared polyphyletic. A new tribe Hymenodictyoneae is created to accommo- date Hymenodictyon and Paracorynanthe. Descriptions and diagnostic features of the newly circum- scribed Naucleeae and Hymenodictyoneae are provided.

Abstract: This study describes floral morphology and phenology, self-incompatibility, and pollen tube growth rates in self- and cross-pollinations of C. occidentalis

Abstract: Annual production of the isopod, Asellus obtusus, and the amphipod, Crangonyx gracilis sp., in a small wetland pond in NW Georgia was estimated using the Hynes method. Both species were found in two distinct vegetation zones: a central Cephalanthus occidentalis zone and a marginal Nyssa biflora zone. In the Nyssa zone, the crustaceans occurred in the aufwuchs and benthos, but in the Cephalanthus zone, only in the aufwuchs. Five samples were taken each month in each of these three habitats during one year to obtain life history and standing stock data. Although growth of each species was relatively asynchronous, they each appeared to have one generation per year. Combined aufwuchs-benthos production in the Nyssa zone was 2.44 g/m2 dry wt for Crangonyx and 1.44 g/m2 for Asellus. Annual turnover ratios were 6.1 and 6.0, respectively. Aufwuchs production in the Cephalanthus zone was 1.63 g/m2 for Crangonyx and 0.65 g/m2 for Asellus. Annual turnover ratios were 6.8 and 8.1, respectively. Benthos in Nyssa contributed by far the greatest crustacean production to this zone based upon standing stock values, but aufwuchs populations were the only significant source of production in the Cephalanthus zone.