Iquitos, PERU

Ph.D Student, University of Missouri-St. Louis

M.S. Biology, University of Missouri-St. Louis

B.S. Biology, National University of the Peruvian Amazon

Research interest:

Morphological evolution and diversification in Menipermaceae

Background:

Menispermaceae, a family composed primarily by lianas with dioecious and small inconspicuous flowers (see image of Odontocarya sp. on left), are distributed primarily in the lowland tropical regions of the world. The family is characterized by its curved endocarp, which is reflected in its common name - "the moonseed family" - (see the image of a seed of Elephantomene eburnea (below right), and Hyperbaena domingensis) as well as the presence of successive cambia. The latter appears as successive rings of several vascular bundles (see image of Curarea tecunarum) and broad or thin radial bands of parenchyma in transverse section (see image of Curarea toxicofera below on the left and Curarea tecunarum). The family are best known as one of the sources of "curare" the South American arrow-poison, and several members (image of Chondrodendron tomentosum) are still used as folk medicine in Brazil, Colombia, Ecuador and Peru .

The complex pattern of morphological variation observed at every level within the family and the scattered distribution of the genera across the globe have generated several questions regarding its phylogenetic affinities. Traditional classifications have stressed characters of the seed, particularly the ornamentation of the endocarp and shape of the condyle (ventral intrusion of the endocarp). However, seeds of many currently recognized genera are still unknown. Hence, these genera are therefore circumscribed by other characters, including the general morphology of the plant and characters of the staminate flowers. Modification of the androecium, involving suppression or fusion of parts, in addition to the displacement of thecae due mainly to the unequal development of the ventral and dorsal connectives, has introduced a remarkable variety of staminal forms. However, it is possible that particular staminal forms have evolved repeatedly in genera that are not closely related.

Earlier studies of wood structure did not reveal substantial differences among neotropical genera and species, but a preliminary investigation of wood anatomy in Curarea has proven useful to separate species groups within the genus. On the other hand, endocarp ornamentation has traditionally provided important taxonomic characters at the generic and specific levels in Menispermaceae. Thus, ornamentations are remarkably pronounced in neotropical Odontocarya (? = Old world Tinospora and Chasmanthera) and Disciphania, and in old world Aspidocarya, Chlaenandra, and Legnephora, where different quite distinctive patterns of raised ornamentations such as crests and very prominent ribs can be observed. Less developed but still noticeable ornamentations that consist of dorsal ridges, spines or tubercles characterize neotropical Cissampelos, and paleotropical Parabaena, Kolobopetalum, Pericampylus, Diploclisia, Cocculus, Limaciopsis, Sarcopetalum, Menispermum, Stephania, Cyclea, Antizoma, Platytinospora, and Hypserpa.

In neotropical genera such as Abuta, Anomospermum, Caryomene, Curarea, Chondrodendron, Hyperbaena, Orthomene, Sciadotenia, and Telitoxicum, the ornamentation is even less pronounced consisting of shallow grooves, less strongly developed dorsal ridges, and incised-veins. The neotropical Borismene and paleotropical Pachygone, Burasaia, Fibraurea, Tinomiscium, Rhigiocarya, Penianthus, Sphenocentrum, Pleogyne, and Synclisia provide extreme examples of genera that lack endocarp ornamentation. Hence, endocarp ornamentation in Menispermaceae presents an excellent opportunity to assess complex patterns of morphological variation in the family. It is hoped that elucidation of inter-generic phylogenetic affinities, based on molecular data, can be used as a framework for investigations of character evolution and evolutionary trends within the family, particularly among its neotropical components.

Current activities:

As part of my dissertation, I am engaged in developing a working molecular phylogeny for the entire family that I can use as a framework to investigate the affinities of more inclusive groups. I will use the phylogeny to predict the morphological diversification of endocarp ornamentation across selected lineages within the family. Thus far, I have completed a world-wide sampling of the genera and species in the family. Currently, I am gathering sequence data for the plastid ndhF gene and exploring the phylogenetic utility of various nuclear markers.

Selected Publications

Menispermaceae. 1997. In: Flórula de las Reservas Biológicas de Iquitos. Missouri Bot. Gard. Systematic Botany Monographs. 63: 457-500.

Menispermaceae.2001. In: Flora de Nicaragua. Missouri Bot. Gard Systematic Botany Monographs 85: 1432-1442.

Menispermaceae. (in press). In: Flórula de Amacayacu (Amazonia, Colombia)

Systematics of Curarea (Menispermaceae) Barneby & Krukoff. MS thesis. University of Missouri St. Louis.

Menispermaceae. In: Flora of the Cenepa Region (Peru ) (mss)

Menispermaceae: Bolivian Checklist (mss.)

Menispermaceae: Flora Mesoamericana (in prep.)

Email: rosa.ortiz-gentry@mobot.org

All images and text copyright Rosa Ortiz-Gentry