September 1999] KRON ET AL.—PHYLOGENETICS OF ANDROMEDEAE 1295 Fig. 1. Strict consensus <strong>of</strong> all most parsimonious trees (36) from analysis <strong>of</strong> morphological data. Length (L) 139, Consistency Index (CI) 0.48, Retention Index (RI) 0.68. Decay values are below lines. Taxa traditionally placed in the tribe Andromedeae are in boldface. strongly supported by the data. Within this clade Vaccinieae are monophyletic and form a polytomy with three other clades. The sister relationship <strong>of</strong> Andromeda polifolia and Zenobia pulverulenta is strongly supported by the matK data and there is strong support for Chamaedaphne calyculata sister to Leucothoë racemosa. These results are different from the morphological analysis (Fig. 1) where Andromeda is indicated as more closely related to the Lyonia group than the Gaultheria group. Similar to the morphological analysis, Lyonia and Pieris are monophyletic in the matK analysis. The Lyonia group (Lyonia, Craibiodendron, Pieris, Agarista) is monophyletic but not very strongly supported. In both the rbcL and matK analyses the Gaultheria group is placed in the same clade with a monophyletic Vaccinieae. In the matK analysis this large clade is strongly supported. The results <strong>of</strong> the rbcL analysis indicate only weak support for a Gaultheria group Vaccinieae clade, with the clade collapsing in trees one step longer than most parsimonious (Fig. 3). The Gaultheria group is not supported as monophyletic by either the rbcL or the matK analyses. Both analyses indicate a core Gaultheria clade that includes Tepuia, Diplycosia, Gaultheria, and Pernettya. In the rbcL analysis Diplycosia is sister to Tepuia, whereas in the matK analysis Diplycosia is included in a polytomy containing Gaultheria and Pernettya. However, none <strong>of</strong> these relationships is strongly supported in either analysis. Combined analysis <strong>of</strong> rbcL and matK data resulted in four most parsimonious trees (L 1495, CI 0.92, RI 0.58). The strict consensus (Fig. 5) is highly resolved with Oxydendrum sister to the remaining ingroup taxa. As in the separate molecular data analyses Agarista, Lyonia, and Pieris are monophyletic, but in the combined analysis they each have higher levels <strong>of</strong> support than in each individual analysis. In the combined rbcL and matK analysis Vaccinieae are monophyletic and unresolved with respect to the Andromeda Zenobia clade and the weakly supported clade that includes Leucothoë, Chamaedaphne, Tepuia, Diplycosia, Gaultheria, and Pernettya. In this analysis Gaultheria is paraphyletic with respect to Pernettya, a relationship also found in the rbcL and morphological analyses. Combined molecular and morphological analysis— This analysis resulted in the generation <strong>of</strong> a single most parsimonious tree <strong>of</strong> 1565 steps, a consistency index (CI) <strong>of</strong> 0.61, and a retention index (RI) <strong>of</strong> 0.59 (Fig. 6). The position <strong>of</strong> Oxydendrum as sister to the remaining ingroup taxa is strongly supported. The monophyly <strong>of</strong> the Lyonia group (incl. Agarista, Craibiodendron, Lyonia, and Pieris) is strongly supported (d8, 99% bootstrap). Noteworthy morphological features supportive <strong>of</strong> the monophyly <strong>of</strong> this group include bands <strong>of</strong> fibers in the phloem (no. 1), leaves with lignified epidermal cells (no. 13), S-shaped filaments (no. 33), and more or less elongated testa cells (no. 57). Within this clade, Agarista likely is sister to Pieris, and Craibiodendron is weakly supported as the sister group <strong>of</strong> Lyonia. Agarista, Pieris, and Lyonia are all strongly supported as monophyletic (Fig. 6); the monophyly <strong>of</strong> Craibiodendron was not assessed. Cladogram topology within the Lyonia group was identical to that discovered in our previous analysis <strong>of</strong> this group (Kron and Judd, 1997), and that paper should be consulted for a more detailed discussion <strong>of</strong> these generic and infrageneric relationships. Vaccinieae form a well-supported clade (d24, 100% bootstrap) with members <strong>of</strong> the Gaultheria group, Andromeda, and Chamaedaphne. A significant morphological synapomorphy <strong>of</strong> this clade is paracytic stomata (no. 20). The Vaccinieae are clearly monophlyetic (d19, 100% bootstrap) and are supported by the same morphological characters as in the morphology-based analyses, with the addition <strong>of</strong> the anther tubules (no. 41). Such tubules evidently have evolved independently in a few other taxa, e.g., Chamaedaphne and the Tepuia Diplycosia clade. The remaining taxa, mainly members <strong>of</strong> the Gaultheria group, form a very weakly supported clade (d1, 50% bootstrap), which possibly is supported by the synapomorphy <strong>of</strong> a base chromosome number <strong>of</strong> 11 (although Andromeda has x 12). In addition, forked appendages (no. 40) occur on the anthers <strong>of</strong> Zenobia, Gaultheria, and Pernettya and may have been lost from the remaining taxa. Within this group, Andromeda and Zenobia are sister to a potential clade (d1, 63% bootstrap) containing Chamaedaphne, Leucothoë, Tepuia, Diplycosia, Gaultheria, and Pernettya. However, a core element, containing Diplycosia, Tepuia, Gaultheria, and Pernettya is well supported (d11, 100% bootstrap). Members <strong>of</strong> this clade are united by the presence <strong>of</strong> methyl salicylate (lost in some species <strong>of</strong> Gaultheria and Diplycosia). They may also share the apomorphy <strong>of</strong> sepals that are fleshy and colorful, but the latter feature is absent in Tepuia (and in some species <strong>of</strong> Pernettya) and may have evolved inde-
1296 AMERICAN JOURNAL OF BOTANY [Vol. 86 Fig. 2. Representative most parsimonious tree (one <strong>of</strong> 36) from the analysis <strong>of</strong> morphological data. Phylogenetically informative characters are mapped onto the tree using ACCTRAN optimization (DELTRAN optimizations are discussed in the text). Solid bars—unique; hatched bars—occur more than once in the tree; open bars—reversals. Taxa traditionally placed in the tribe Andromedeae are in boldface.
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