The delimitation of genera within the Persea group (Lauraceae) has always been controversial. In an attempt to resolve the phylogenetic lines within this group, we analyzed ITS sequences of 61 species of the Persea group (Lauraceae) and 30 other species of Lauraceae. Several of the traditional genera or subgenera form wellsupported groups, viz., Persea subg. Eriodaphne, Machilus, Persea subg. Persea, and Alseodaphne including Dehaasia. The included species of Phoebe form two clades that are unresolved with respect to Alseodaphne. However, Persea subg. Eriodaphne (together with the Macaronesian Apollonias barbujana) forms one of the clades of an unresolved basal trichotomy within the Persea group, whereas Persea subg. Persea is well supported as member of an otherwise Asian clade including Alseodaphne and Phoebe. This indicates that Persea, as currently circumscribed, is not monophyletic. The affinities of the Macaronesian Persea indica are clearly American rather than Asian.
A phylogenetic analysis based on nuclear ITS and plastid trnK intron sequences confirms that Dahlgrenodendron, Sinopora, Triadodaphne, and Yasunia are members of the Cryptocarya group, as expected from morphology. Dahlgrenodendron from South Africa is sister to Aspidostemon from Madagascar. Triadodaphne inaequitepala is nested within Endiandra (both from Australasia), and Yasunia from South America is nested among South American Beilschmiedia species. Sinopora is a member of the Beilschmiedia clade, but its precise position is still uncertain. Among large genera of the group, Cryptocarya is clearly monophyletic, and Endiandra appears to be as well, if T. inaequitepala is included. Beilschmiedia is paraphyletic with respect to (at least) Potameia and Yasunia. Most wellsupported clades within genera are geographically homogeneous, except a clade including the Chilean Cryptocarya alba and two New Caledonian species. Both Beilschmiedia and Cryptocarya have reached the Americas more than once. Four-locular anthers are plesiomorphic in the Cryptocarya group; two-locular anthers have arisen by fusion of the two pollen sacs of a theca. In the plesiomorphic fruit type, the ovary is completely enclosed in receptacular tissue; a superior fruit, seated free on its pedicel, is a synapomorphy of the Beilschmiedia clade.
Earlier studies indicated that the genus Nectandra, currently the second‐largest genus of the Neotropical Lauraceae, might be diphyletic in its traditional circumscription, but the evidence was not quite conclusive. Our phylogenetic analyses based on nuclear (ITS) and chloroplast (psbA‐trnH) sequences of 45 Nectandra species as well as 42 representatives of 18 genera of the core Lauraceae (Ocotea complex, Laureae, Aiouea, Asian Cinnamomum and Persea groups) confirm the suspicion that Nectandra is diphyletic. The two groups, Nectandra s.str. and the N. coriacea group, are each well supported in the maximum parsimony and Bayesian analyses, but they are not sister to each other. Nectandra s.str. is sister to Pleurothyrium, and the clade including Nectandra s.str. and Pleurothyrium is very likely closer to the dioecious taxa of the Ocotea complex. The N. coriacea group, on the other hand, appears to be closer to bisexual taxa known as the Ocotea helicterifolia group. In addition, Nectandra s.str. is characterized by a large deletion in the psbA‐trnH spacer compared to all other core Lauraceae, including its sister group Pleurothyrium. Considering these facts, Nectandra cannot be maintained in the traditional sense. We therefore transfer the species of the N. coriacea group to the oldest generic name applied to this group, Damburneya. On the basis of fossil records from the American subcontinents and in accordance with previous phylogenetic and molecular clock studies we suggest a scenario of a climate‐driven migration from North to South America, with a subsequent rapid radiation of Nectandra s.str. in South America.
Cinnamomum is among the largest genera of the Lauraceae, including species from tropical to temperate Asia and from tropical to subtropical America. However, previous studies indicated that Cinnamomum might not be monophyletic in its current circumscription. We therefore re‐investigated the genus and possible relatives with an increased taxon sample, particularly of the Neotropical species. Our results, based on sequences of the nuclear ITS region and the chloroplast spacers psbA‐trnH and trnG‐trnS, show that the Neotropical Cinnamomum species indeed do not form a monophyletic group with the Paleotropical species. Instead, the American species form a clade in which most species of the Neotropical genus Aiouea are nested within several subclades. According to the ITS data the Aiouea/Cinnamomum clade is sister to the likewise predominantly Neotropical Ocoteacomplex, rather than the two Paleotropical Cinnamomum clades. Therefore, Cinnamomum cannot be upheld in its cur‐rent circumscription. As the type C. verum, is from Asia, the Neotropical species need to be placed in a different genus. We decided to transfer them to Aiouea here, because this is the oldest generic name in the Aiouea/Cinnamomum clade, and the only character separating Aiouea from Neotropical Cinnamomum is the number of pollen sacs per anther (di‐ vs. tetrasporangiate), a feature that is known to be variable within several other genera as well. This transfer requires 42 new combinations and two nomina nova. In addition, six species described in the unpublished Ph.D. thesis of one of the authors (FLH) are validated in Aioueahere, and the only species of the genus Mocinnodaphne is transferred to Aiouea as well.
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