CHLORANTHACEOUS FLORAL STRUCTURES FROM THE LATE CRETACEOUS OF SWEDEN

New chloranthaceous floral structures from the Late Cretaceous (Late S antonian/Early Campanian) of Scania, southern Sweden, have provided im portant new information on the Chloranthistemon plants. The material i ncludes well preserved fragments of inflorescence axes with flowers in situ documenting that Chloranthistemon flowers were bisexual and clos ely resembled those of extant Chloranthus (Chloranthaceae), An emended diagnosis is given for the type species of the genus, Chloranthistemo n endressii, and a new species, C. alatus, is described. The flowers o f Chloranthistemon are small, perianthless and strongly zygomorphic, c onsisting of a tripartite and broadened androecium borne in an abaxial to lateral position on the monocarpellate ovary, and arranged in the axils of decussate bracts. Stamens are either completely free (C. alat us), or free at the base and coherent at the apex (C. endressii). The apical connective is extensive in both species; elaborated into conspi cuous wing-like structures in C. alatus, or into a massive and shield- like structure in C. endressii. Pollen grains of C. endressii are sphe roidal, and reticulate and spiraperturate, while chose of C. alatus ar e ellipsoidal, tectate and foveolate with a unique combination of a di stal colpus and a proximal furrow (colpus?) perpendicular to each othe r. Ovaries observed in well preserved flowers of both species are smal l and undifferentiated. Larger, dispersed fruits of chloranthaceous af finity are abundant and distinct, and probably represent at least two or three species, but cannot be linked with certainty to any of the Ch loranthistemon species described here.