Kathleen R. Reitsma

Morphometrics of Daucus (Apiaceae): A counterpart to a phylogenomic study

PREMISE OF STUDY Molecular phylogenetics of genome-scale data sets (phylogenomics) often produces phylogenetic trees with unprecedented resolution. A companion phylogenomics analysis of Daucus using 94 conserved nuclear orthologs supported many of the traditional species but showed unexpected results that require morphological analyses to help interpret them in a practical taxonomic context. METHODS We evaluated character state distributions, stepwise discriminant analyses, canonical variate analyses, and hierarchical cluster analyses from 40 morphological characters from 81 accessions of 14 taxa of Daucus and eight species in related genera in an experimental plot. KEY RESULTS Most characters showed tremendous variation with character state overlap across many taxa. Multivariate analyses separated the outgroup taxa easily from the Daucus ingroup. Concordant with molecular analyses, most species form phenetic groups, except the same taxa that are problematical in the molecular results: (1) the subspecies of D. carota, (2) D. sahariensis and D. syrticus, and (3) D. broteri and D. guttatus. CONCLUSIONS Phenetic analyses, in combination with molecular data, support many Daucus species, but mostly by overlapping ranges of size and meristic variation. The subspecies of D. carota are poorly separated morphologically, are paraphyletic, and all could be recognized at the subspecies rank under D. carota. Daucus sahariensis and D. syrticus are so similar morphologically that they could be placed in synonymy. Combined molecular and morphological data support three species in accessions previously identified as D. broteri and D. guttatus. Molecular and morphological results support the new combination Daucus carota subsp. capillifolius.

Lectotype Designation for Seven Species Names in the Daucus guttatus Complex (Apiaceae) from the Central and Eastern Mediterranean Basin

Abstract The Daucus guttatus complex includes two to four species growing from central and northern Italy to the Middle East. They are characterized by being typically annuals up to 50 cm high; with primary umbels up to 7 cm in diameter with fewer than 25(35) rays; discolored umbels frequent, bearing one to several dark colored umbellules which form different color patterns; and mericarps relatively small, ca. 2.0–4.5 mm. The taxonomy of this complicated group has not been satisfactorily resolved to date and is the focus of current research. Seven names of species belonging to the D. guttatus complex occurring in the central and eastern Mediterranean basin are typified here: Daucus guttatus, Daucus bicolor, Daucus involucratus, Daucus setulosus, Daucus broteri, Daucus hirsutus, and Daucus speciosus. Historical data are reported to justify lectotype and/or epitype selection, and selected morphological and distributional data are used to facilitate identification. The resulting typifications will enable proper naming of clades identified in the accompanying integrated molecular and morphological study, clarifying the taxonomy of the Daucus guttatus complex.

Cucumis zambianus (Cucurbitaceae), a New Species from Northwestern Zambia

Abstract During germplasm explorations within Zambia in 1984, seven Cucumis accessions were collected that could not be identified to species. Two of the accessions were studied in-depth. Based on phenotypic characters, they were closest to Cucumis pustulatus. In ITS analyses of all available Cucumis species and the accessions, the two accessions grouped with 100% bootstrap support in a clade comprising C. anguria, C. dipsaceus, C. insignis, and C. pustulatus. The accessions differed from these four Cucumis species by the following characters: plants pilose, male inflorescences paniculate with 6–30 flowers, staminate-flower calyx lobes linear, pistillate-flower pedicels long and cylindrical, and a genetic difference of 4 base pairs in their ITS sequences. Controlled crosses were made within and between the two accessions and between each of them and C. pustulatus. Fruits were produced from crosses made within and between the two accessions, but attempts involving C. pustulatus were unsuccessful. The two accessions are described as a new species, Cucumis zambianus. Six of the seven unidentified Cucumis collections from Zambia are identified as C. zambianus herein. They were all collected in the northwestern corner of Zambia, but the new species is also expected to occur in eastern Angola and southern Zaire.