|
The systematic affinities of Anemoclema and its taxonomic rank within tribe Anemoneae of Ranunculaceae have long been in dispute. Anemoclema glaucifolium has traditionally been treated according to morphology within Anemone (including the Pulsatilla group), where it may represent a transition from Anemone towards Clematis or as its own, monotypic genus. However, the most recent molecular phylogenetic studies showed that Anemoclema was more closely related to Clematis than to Anemone. In order to help resolve the position of Anemoclema, we used light and scanning electron microscopy to study the morphology and development of the flower of Anemoclema glaucifolium. Our results support a close affinity of Anemoclema within Anemoneae on the basis of several floral developmental and morphological features: (1) broad and crescent-shaped young sepals, (2) narrow and rounded stamen primordia, (3) carpels ascidiate, stigma papillate, decurrent, (4) carpels bearing one median fertile ovule and a few lateral sterile ovules, (5) the fertile ovule appearing before the carpel closes, and (6) anatropous and unitegmic ovule. At the same time, Anemoclema also shared some characteristics with Clematis that are not present in Anemone: (1) stem leaves opposite (vs. stem leaves absent), (2) centripetal anther maturation (vs. centrifugal or bidirectional), and (3) conspicuous appendage at the ventral base of the ovule funicle (vs. inconspicuous appendage). Thus, our findings support the placement of Anemoclema within the tribe Anemoneae and its closer relationship to Clematis than to Anemone on the basis of floral morphogenesis. These conclusions are corroborated by previous molecular phylogenetic studies. |
|
Keywords:Anemoclema; floral development; flower morphology; Ranunculaceae |
|