Systematics Section, BSA / ASPT / IOPB 466 HARDY, CHRISTOPHER R.1,2*, JERROLD I DAVIS1, breeding system. This effectively reproductively isolates the species. ROBERT B. FADEN3, AND DENNIS W. STEVENSON1,2 Previous studies have provided extensive genetic, phylogenetic and 1Bailey Hortorium, Cornell University, Ithaca, NY 14853; 2New York natural selection data which allow for a rare opportunity to now Botanical Garden, Bronx, NY 10458; 3Dept. of Botany, National study and interpret ontogenetic changes as sources of evolutionary Museum of Natural History, Smithsonian Institution, Washington, novelties in floral form. Three populations of M. cardinalis and four DC 20560 populations of M. lewisii (representing both described races) were studied from initiation of floral apex to anthesis using SEM and light Phylogenetics of Cochliostema, Geogenanthus, and microscopy. Allometric analyses were conducted on data derived an undescribed genus (Commelinaceae) using from floral organs. Sympatric populations of the species from morphology and DNA sequence data from 26S, 5S- Yosemite National Park were compared. Calyces of M. lewisii initi- NTS, rbcL, and trnL-F loci ate later than those of M. cardinalis relative to the inner whorls, and sepals are taller and more acute. Relative times of initiation of phylogenetic study was conducted on a group of three small petals, sepals and pistil are similar in both species. Petal shapes dif- genera of neotropical Commelinaceae that exhibit a variety fer between species throughout development. Corolla aperture of unusual floral morphologies and habits. Morphological A shape becomes dorso-ventrally narrow during development of M. characters and DNA sequence data from plastid (rbcL, trnL-F) and lewisii, and laterally narrow in M. cardinalis. In both species, the nuclear ribosomal (5S-NTS, partial 26S) loci were used. In separate adaxial filaments curve adaxially as they elongate. In M. lewisii, the analyses, 26S and rbcL character sets each yielded cladograms that abaxial stamens curve away from the median while those of M. car- were equally or more fully resolved than those from analyses of the dinalis are directed adaxially. Allometric analyses reveal that differ- more rapidly-evolving 5S-NTS and trnL-F loci. Analysis of the ences in corolla length dimensions between species are controlled molecular character sets, in combination with morphological char- by alterations in rate of growth, while differences in stamen and pis- acters, has provided a framework for the study of life form and mor- til dimensions are controlled by alterations in timing of termination phological character evolution. Our studies indicate that the of growth relative to corolla growth. unusual spirally-coiled anthers and other apparent autapomorphies in the flowers of Cochliostema are elaborations of developmental synapomorphies shared by Cochliostema with Geogenanthus and 469 HEARN, DAVID JOHN an undescribed genus. The adaptations associated with the epi- University of Arizona, Dept. of Ecology and Evolutionary Biology, phytic habit of Cochliostema are best understood in light of their BSW Room 310, Tucson, AZ 85721-0088 similarity to homologous features in the undescribed genus. Our Growth form evolution in Adenia and correlations inclusion in this study of two undescribed plesiomorphic species of with phytochemistry Geogenanthus has revealed an evolutionary trend towards reduc- tion in the inflorescence in this genus. he genus Adenia (Passifloraceae) provides a model system with which to investigate the relationship between growth 467 HAYNES, ROBERT R.*, CHARLOTTE LINDQVIST, Tform and phytochemistry. With ca. 90 species the genus has AND VICTOR A. ALBERT a diverse and varied pharmacopoeia and at least seven distinct Biodiversity and Systematics, Dept. of Biological Sciences, The growth forms. An association between growth form and chemistry University of Alabama, Tuscaloosa, AL 35487-0345 is expected based on theoretical predictions. I mapped cyanogen- esis on the phylogeny of Adenia to reveal that 4 of the 5 putative Molecular systematics of Potamogeton shifts from ancestral tendrillate vines to growth forms without ten- (Potamogetonaceae) drils are in association with low cyanogenesis as expected. The phylogeny based on ITS sequence data and an extensive sampling he pondweeds, Potamogeton (Potamogetonaceae), display of African and Madagascan species of Adenia supports 5 main lin- heterophylly, both within and among species. In addition, eages. Extrafloral nectary superstructure in large part supports the some species display seasonal heterophylly. Consequently, T molecular characterization. Individuals in the most basal lineage of the genus has long been considered to be taxonomically difficult. Adenia all possess spatulate glands at the leaf blade base. The next Potamogeton, sensu stricto, has conveniently been divided into two most ancient lineage has members that are tuberous vines and groups, broad-leaved species and narrow-leaved species. herbs. Members of this lineage share paired and upturned glands Phylogenetic analysis of 5S nuclear ribosomal non-transcribed at the petiole-blade junction. A more recent lineage contains a wet- spacer (5S-NTS) sequences supports the monophyly of two major tropical African lineage and a dry-habitat African and Madagascan clades, one essentially those previously considered to be broad- lineage. The wet-tropical lineage has lianas and vines with paired leaved species and the other those previously considered to be nar- auriculate glands at the blade-petiole junction. The dry-habitat row-leaved species. Within each main clade, species groups are African and Malagasy lineage possesses species with succulence recognized, mostly along the lines of previously accepted subsec- and often slightly recessed glands at the base of the leaf (although tions. For example, Potamogeton epihydrus and P. tennesseensis some Madagascan species are autopomorphic). The lineage that is form a clade sister to the P. spirillus, P. bicupulatus, and P. diversi- sister to this more recent branch is least characterized by gland folius clade. These two subclades are in turn sister to the species structure, but possesses a diversity of gland structures and growth previously recognized as the narrow-leaved pondweeds. forms. Research is underway to relate anatomical features with phy- tochemistry to rigorously test whether changes in anatomy (hence 468 HAZLE, THOMAS* AND JUDITH M. CANNE-HILIKER changes in growth form) are correlated with changes in phyto- Dept. of Botany, University of Guelph, Guelph, ON. N1G 2W1 chemistry. Ontogenetic floral evolution of Mimulus lewisii and M. cardinalis (formerly Scrophulariaceae, s.l.): allometry and morphology peciation in the bee-pollinated Mimulus lewisii and bird-polli- nated M. cardinalis group is hypothesized to have occured Sthrough divergence in floral form that led to a change in ABSTRACTS 117 Systematics Section, BSA / ASPT / IOPB 470 HELFGOTT, D. MEGAN1* AND BERYL B. SIMPSON2 bootstrap). A clade of asterids and Caryophyllales appears as sister 1Dept. of Biological Sciences, University of Idaho, P.O. Box 443051, to Berberidopsidales. Asterids consist of a well- supported clade Moscow, ID, 83844; 2Section of Integrative Biology and the Plant composed of Ericales, Cornales, and euasterids. Within rosids most Resources Center, The University of Texas, Austin, TX, 78712 of the currently recognized orders gain good support. Moreover, matK sequences provide good resolution within many of the orders Phylogenetics of Nemophila using molecular and of angiosperms. morphological data 1 1 he North American endemic genus Nemophila 472 HOGGARD, RON *, PAUL KORES , MIA 1 1 (Hydrophyllaceae) consists of 11 species and six varieties of MOLVRAY , GLORIA HOGGARD , AND DAVID 2 annual herbs found primarily in California. Nine species BROUGHTON T 1Dept. of Botany and Microbiology, University of Oklahoma, occur in the western United States as far south as Baja California, while two species (N. phacelioides and N. aphylla) are disjunct in Norman, OK 73019; 2Dept. of Applied Plant Science, The Queen's the southeastern United States. The evolutionary relationships University of Belfast, Belfast, BT9 5PX within Nemophila remain unclear despite eight previous taxonomic Molecular systematics and biogeography of the treatments and exploration of a variety of potentially useful kinds amphibious genus Littorella (Plantaginaceae) of characters (morphology, cytology, and development). We pres- ent a phylogenetic analysis of Nemophila and relevant taxa in the ittorella is a small, amphibious genus within the tribe Hydrophylleae using DNA sequence data from both the Plantaginaceae and is represented by three closely related, nuclear ribosomal DNA internal transcribed spacer, and from the Ldisjunct species, L. uniflora (L.) Ascherson in Europe includ- chloroplast 3’ trnK intron. The molecular phylogenetic analyses co- ing Iceland and the Azores, L. americana Fernald in North America, ncur with infratribal relationships previously inferred from seed coat and L. australis Griseb. ex Bentham & Hooker in southern South characters. On our phylogeny Nemophila and Pholistoma form an America. A recent phylogeny (Rahn, 1996) based on morphologi- unresolved polytomy, but seed coat morphology suggests that cal, embryological, and chemical data has resulted in the reduction Pholistoma is sister to Nemophila as a whole. Within Nemophila of Littorella to Plantago subgenus Littorella (P.J. Bergius) Rahn and seven of