Astrodaucus

Abstract: Since the tribe Caucalideae was recognized by Bentham and later Boissier for those species of Apiaceae (Umbelliferae) with spines, hooks, tubercles or bristly hairs on the primary and/or secondary ridges of their fruits, there has been considerable disagreement as to its proper circumscription, the relation- ships among its members, and the delimitation of certain genera. A recent checklist of the group recognized 68 species in 21 genera; a previous molecular systematic study, however, excluded Aphanopleura and Psam- mogeton from the tribe. Phylogenetic relationships among all but one of the 19 remaining genera (material from the rare, monotypic genus Angoseseli was not available for examination) and representatives from pu- tatively allied tribes Scandiceae, Laserpitieae, Apieae, and Smyrnieae were inferred from nucleotide sequence variation in the internal transcribed spacer regions of 18S-26S nuclear ribosomal DNA. In all, 29 genera representing 58 taxa were examined. Phylogenies estimated using maximum parsimony, maximum likeli- hood, and neighbor-joining methods give trees of essentially similar topology, and reveal three major lineages of equivocal relationship: (1) Agrocharis, Ammodaucus, Artedia, Cuminum, Daucus, Laser, Laserpitium, Orlaya, Polylophium, Pseudorlaya, and Pachyctenium; (2) Astrodaucus, Caucalis, Chaetosciadium, Glochidotheca, Lisaea, Szov- itsia, Torilis, Turgenia, and Yabea; and (3) Anthriscus, Kozlovia, Myrrhis, Osmorhiza, and Scandix. These groups are provisionally named the Daucus, Torilis, and Scandix subclades, respectively, of a previously delimited Daucus clade. The first subclade contains representatives of Drude's tribe Laserpitieae, whereas the third subclade coincides with Heywood's tribe Scandiceae. Based on those species included in the study, the genera Daucus, Laserpitium, and Torilis are each not monophyletic. Members of tribe Caucalideae Spreng. (Apiaceae; Umbelliferae) are distributed throughout Europe, the Mediterranean region, and southwestern and central Asia, with a few outlying members in North America. Of the 21 genera and 68 species listed in the most recent checklist for the tribe (V. Heywood and S. Jury in Heywood 1982c; Table 1), Daucus is the largest genus with 21 species, followed by To- rilis with 10 species. Daucus is also by far the most economically important member of the tribe, if not the entire family. Three species of Caucalideae are native to the New World: Daucus montanus Humb. & Bonpl., D. pusillus Michx., and Yabea microcarpa (Hook. & Arn.) Koso-Pol. Classification of Apiaceae has been based largely on anatomical and morphological features of the mature fruit (Heywood and Dakshini 1971; Hey-