Plant Syst. Evol. 221:35-60 (2000) Plant Systematics and Evolution © Springer-Verlag 2000 Printed in Austria Phylogenetic analysis of cpDNA restriction sites and rpsl6 intron sequences reveals relationships among Apiaceae tribes Caucalideae, Scandiceae and related taxa B.-Y. Lee and S. R. Downie Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA Received February 14, 1999 Accepted August 10, 1999 Abstract. Evolutionary relationships among mem- within Torilis, and is recognized as Torilis tricho- bers of Apiaceae (Umbelliferae) tribe Caucalideae sperma (L.) Spreng. Spreng. and related taxa were inferred from max- imum parsimony analyses of chloroplast DNA Key words: Caucalideae, Scandiceae, Apiaceae, restriction sites and rpsl6 intron sequences and the Umbelliferae, chloroplast DNA restriction sites, results compared to an existing phylogeny for the rpsl6 intron. group based on nuclear ribosomal DNA internal transcribed spacer sequences. While these three data sets were not similar in size or composition, Introduction the relationships among the shared taxa, with few Tribe Caucalideae Spreng., as defined by exceptions, were concordant. Three major lineages Bentham (1867) and later Boissier (1872), are recognized, coinciding with the previously delimited Scandiceae subtribes Daucinae Dumort. contains practically all of those species of (Agrocharis, Ammodaucus, Cuminum, Daucus, Apiaceae (Umbelliferae) that have spines, Orlaya, Pachyctenium, Pseudorlaya), Torilidinae hooks, tubercles, or bristly hairs on the Dumort. (Astrodaucus, Caucalis, Glochidotheca, primary and/or secondary (vallecular) ridges Lisaea, Szovitsia, Torilis, Turgenia, Yabea), and of their fruits. Uniquely in this group, the Scandicinae Tausch (Anthriscus, Kozlovia, Myrrhis, secondary ridges are often more strongly Osmorhiza, Scandix). Included in Daucinae is developed than the primary. These plants are representation from tribe Laserpitieae (Laser, Lase- distributed throughout Europe, the Mediter- rpitium, Melanoselinum, Monizia, Polylophium). ranean region, and southwestern and central Daucinae and Torilidinae arise as sister taxa in Asia, with a few outlying members in North the chloroplast DNA-based phylogenies, whereas and South America and Australia. Of the 21 in the ITS trees relationships among the three genera and 68 species recognized in the tribe major lineages are unresolved. Unexpectedly, three species of Ferula ally with Daucinae and Torili- (Heywood and Jury in Heywood 1982c), dinae. The position of Artedia is equivocal, occur- Daucus is the largest genus with 21 species ring either sister to Daucinae in the ITS trees, within followed by Torilis with 10 species. Torilidinae in the intron trees, or sister to Torilid- In the most widely used revision of the inae upon analysis of combined ITS and intron family, Drude (1897 1898) redistributed these data. Chaetosciadium trichospermum emerges spiny-fruited plants between his divergent 36 B.-Y. Lee and S. R. Downie: Chloroplast DNA Phylogeny of Tribe Caucalideae Scandiceae subtribe Caucalidinae and tribe the multidisciplinary approaches used to ana- Dauceae. Drude believed that members of lyse these data, fundamental disagreements tribe Dauceae (e.g. Daucus), having spines on still exist regarding the proper circumscription their prominent secondary fruit ridges, are of tribe Caucalideae, the relationships among allied to plants in tribe Laserpitieae (e.g. its members, and the delimitation of certain Laserpitium and Polylophium), whose members genera. Moreover, the relationship between have fruits without spines but with primary Heywood's tribes Caucalideae and Scandiceae and prominent secondary ridges. In contrast, is also quite unclear. the genera of Scandiceae subtribe Caucalidinae In all phylogenetic analyses of molecular (e.g. Caucalis, Orlaya, and Torilis) are linked data to date, whether derived from DNA (by the common possession of calcium oxalate sequences of chloroplast introns or genes, crystals in the parenchyma cells surrounding chloroplast DNA (cpDNA) restriction sites, the carpophore) to those in Scandiceae sub- or nuclear ribosomal DNA (rDNA) internal tribe Scandicinae (e.g. Anthriscus and Scan- transcribed spacer (ITS) sequences, a close dix), the latter subtribe lacking both secondary relationship between Apiaceae tribes Cauca- ridges and spines. Drude assumed that the lideae and Scandiceae is apparent (Downie secondary spinose ridges characteristic of some et al. 1996, 1998; Downie and Katz-Downie Caucalidinae had evolved independently from 1996; Katz-Downie et al. 1999; Plunkett et al. those in Dauceae. Other treatments exist for 1996; Plunkett and Downie 1999). However, these plants, such as those proposed by Cale- while some trees show that Caucalideae and stani (1905), Koso-Poljansky (1916, 1917), and Scandiceae are monophyletic sister taxa, oth- Cerceau-Larrival (1962, 1965), but have not ers indicate that Caucalideae is paraphyletic gained wide acceptance. with Scandiceae nested within. Alternatively, As a result of two international symposia the marK study of Plunkett et al. (1996) (Heywood 1971a, Cauwet-Marc and Carbon- shows a paraphyletic Scandiceae with includ- nier 1982) and a major cooperative research ed Caucalideae. Because the purpose of each program (reviewed in Heywood 1982a, c), the of these studies was not to resolve the spiny-fruited umbellifers have received much intergeneric relationships within tribes Cau- systematic attention. The multidisciplinary re- calideae and Scandiceae but rather to infer the search undertaken, incorporating results from higher-level groupings within the family, the the fields of scanning electron microscopy, number of taxa sampled from each tribe was biochemical systematics, cytology, and numer- small. ical taxonomy, culminated in changes to the We have recently addressed issues of rela- prevailing taxonomy. Here Drude's Dauceae tionship among the spiny-fruited umbellifers and Scandiceae subtribe Caucalidinae were and related taxa by carrying out, with expand- reunited as tribe Caucalideae (Heywood ed sampling, phylogenetic analyses of nuclear 1968a, 1971c; Crowden et al. 1969; McNeill rDNA ITS sequences (Lee and Downie 1999). et al. 1969; Heywood and Dakshini 1971; Fifty-eight accessions, representing 18 of 21 Harborne and Williams 1972; Williams and genera of Caucalideae (Aphanopleura, Psam- Harborne 1972), and Drude's Scandiceae sub- mogeton, and the rare, monotypic Angoseseli tribe Scandicinae was treated at the tribal level, were not considered) and putatively allied taxa Scandiceae Spreng. (Heywood 1971b). Of the from Heywood's Scandiceae and Drude's 21 genera provisionally recognized in Caucal- tribes Apieae, Laserpitieae, and Smyrnieae, ideae (Heywood and Jury in Heywood 1982c), were examined and analyzed using maximum two (Aphanopleura and Psammogeton) have parsimony, maximum likelihood, and neigh- been excluded from the group (Pimenov and bor-joining methods. The results of the max- Leonov 1993, Katz-Downie et al. 1999). How- imum parsimony analysis are presented in ever, despite the wealth of available data and Fig. 1. Here three major lineages are recog- B.-Y. Lee and S. R. Downie: Chloroplast DNA Phylogeny of Tribe Caucalideae 37 nized, designated as Scandiceae subtribes Materials and methods Daucinae Dumort. (1827), Torilidinae Terminal taxa. The 52 accessions considered in this Dumort. (1827), and Scandicinae Tausch study, with corresponding source and voucher (1834; Downie et al. 2000). These taxa coincide information, are listed in Table 1. Thirty-two with the previously delimited "Daucus," accessions were included in the mapping of cpDNA "Torilis," and "Scandix" subgroups (Lee and restriction sites and 34 accessions were sequenced Downie 1999) of the "Daucus" clade (Plunkett for the chloroplast rpsl6 intron, with 14 accessions et al. 1996, Downie et al. 1998, Plunkett and common to both analyses. While each data set was Downie 1999). Subtribes Daucinae and Tori- approximately similar in size, 14 genera were lidinae coincide approximately with Hey- included in the restriction site study (where em- wood's (1982c) tribe Caucalideae but with the phasis on sampling was placed on Daucus and inclusion of four genera of Laserpitieae and Torilis), whereas 27 genera were included in the intron study (where emphasis on sampling was the exclusion of Kozlovia. placed on Laserpitieae and Ferula). The genus We now continue our investigations of Ferula, treated in Drude's tribe Peucedaneae and Caucalideae phylogeny by incorporating data thus considered distantly related to the spiny- from the chloroplast genome. Congruence of fruited umbetlifers, allies with Torilis in the ITS relationship from independent lines of evi- study of Valiejo-Roman et al. (1998) and, as such, dence is necessary in order to examine the was included in our investigation. These 52 acces- robustness of earlier phylogenetic hypotheses sions represent 15 of the 21 genera recognized most and to identify discrepant organismal and recently in Caucalideae (Heywood and Jury in gene phylogenies. Here we use cladistic anal- Heywood 1982c). The six remaining genera were ysis of cpDNA restriction sites and chloro- not included due to lack of sufficient material or, as plast rps16 intron sequences to infer historical in the case of Aphanopleura and Psammogeton, relationships. The latter was chosen because because previous studies had supported their removal from the tribe (Pimenov and Leonov of its potential for variation,