Siphonodon

Abstract: Phylogenetic relationships within Celastraceae were inferred using a simultaneous analysis of 61 morphological characters and 1123 base pairs of phytochrome B exon 1 from the nuclear genome. No gaps were inferred, and the gene tree topology suggests that the primers were specific to a single locus that did not duplicate among the lineages sampled. This region of phytochrome B was most useful for examining relationships among closely related genera. Fifty-one species from 38 genera of Celastraceae were sampled. The Celastraceae sensu lato (including Hippocrateaceae) were resolved as a monophyletic group. Loesener’s subfamilies and tribes of Celastraceae were not supported. The Hippocrateaceae were resolved as a monophyletic group nested within a paraphyletic Celastraceae sensu stricto. Goupia was resolved as more closely related to Euphorbiaceae, Corynocarpaceae, and Linaceae than to Celastraceae. Plagiopteron (Flacourtiaceae) was resolved as the sister group of Hippocrateoideae. Brexia (Brexiaceae) was resolved as closely related to Elaeodendron and Pleurostylia. Canotia was resolved as the sister group of Acanthothamnus within Celastraceae. Perrottetia and Mortonia were resolved as the sister group of the rest of the Celastraceae. Siphonodon was resolved as a derived member of Celastraceae. Maytenus was resolved as three disparate groups, suggesting that this large genus needs to be recircumscribed.

Abstract: SUMMARY The leaf epidermal characters of 89 species belonging to 42 genera of the Celastraceae sensu lato (including Hippocrateaceae) are described in detail. The range and pattern of variation in stomatal type and presence and type of crystalliferous epidermal cells can be used to support the broad family concept of Celastraceae. The stomata may be anisocytic, complex anisocytic, anomocytic, cyclocytic, bi- and/or tricyclic, complex cyclocytic, laterocytic, complex laterocytic, paracytic, parallelocytic, helicocytic, or of an intermediate type. The laterocytic stomata are most common, and are here recognized for the first time as a distinct stomatal type characterized by the lateral position of the subsidiary cells (3 or more) but yet different from the paracytic and cyclocytic type. The general implications of the epidermal diversity for the grouping of genera in a natural classification are discussed. Special attention is devoted to the taxonomic position and/or delimitation of the following genera: Kokoona and Lophopetalum; Sarawakodendron; Perrottetia; Salada and the related genera Cheiloclinium, Peritassa and Tontelea; Hippocratea and the putatively related genera Antodon, Apodostigma, Cuervea, Elachyptera, Helictonema, Hemiangium, Hylenea, Loeseneriella, Prionostemma, Pristimera, Reissantia and Simirestis; Cassine sensu lato (including Elaeodendron, Crocoxylon and Mystroxylon); Denhamia and Maytenus; Euonymus; Goupia; Siphonodon and Pottingeria. Finally a tentative discussion of the wider affinities of Celastraceae is given and the scope for future studies is indicated.

Abstract: The phylogeny of Celastraceae subfamilies Cassinoideae (120 species in 17 genera in both the Old and New World tropics and subtropics) and Tripterygioideae (39 species in seven genera) was inferred using plastid (matK, trnL-F) and nuclear (ITS and 26S rDNA) loci together with morphological characters. Subfamily Cassinoideae include those Celastraceae genera with drupes, berries, or nuts that have one to five locules and one to two seeds per locule, while Tripterygioideae include those genera with one to two seeded samaras that lack arillate seeds. We infer that both subfamilies are grossly polyphyletic groups, with Cassinoideae consisting of ≥ eight separate lineages and Tripterygioideae consisting of ≥ six separate lineages. Crossopetalum, from tropical America, is part of an early derived lineage sister to a taxonomically diverse Austral-Pacific clade. Myginda is not distinct from Crossopetalum. Gyminda + Orthosphenia + Rzedowskia + Schaefferia are a clade that is only distantly related to Cros...

Abstract: In traditional classifications Celastrales comprised families of usually woody plants with simple leaves, haplostemonous flowers with a disk and apotropous ovules which, in view of this character combination, formed an utterly heterogeneous assemblage. In the classification of Engler and Gilg (1912), for instance, families as divergent as Buxaceae, Rhamnaceae, Aquifoliaceae and Balsaminaceae were dumped into their Sapindales (= Celastrales). In later classifications, most authors gave up this broad circumscription but the Celastrales of Takhtajan (1987), to give just one example, comprised 12 families of which nine, according to our present knowledge, would have to be excluded from this order. In the absence of convincing morphological evidence, only sequ-ence-based phylogenetic studies have led to the recognition of a monophyletic order Celastrales which represents a clade of eurosids I that is sister to Oxalidales + Malpighiales, these three being sister to all remaining eurosids I (Fagales, Rosales, Zygophyllales, Curcurbitales, Fabales; Savolainen, ay et al. 2000; Soltis et al. 2000; APG II 2003). The Celastrales clade comprises only three families, Lepidobotryaceae, Celastraceae s.l. and Parnassi-aceae. The rbcL analysis by Savolainen, Fay et al. (2000) provided strong support for a position of Lepidobotryaceae as sister to the other two families. Parnassiaceae, comprising Parnassiaand Lepuropetalum, have often been included in Saxifragaceae. There exists, however, strong morphological (see Simmons on Parnassiaceae, this volume) and molecular evidence for their exclusion from Saxifragaceae. Various analyses of plastid and nuclear genes (Savolainen, Chase et al. 2000; Soltis et al. 1997, 2000) have resolved Parnassiaceae as sister to Celastraceae. In a multi-gene analysis of Celastraceae (Simmons et al. 2001b), Parnassia and Lepuropetalum have been resolved as members of an early branching but weakly supported lineage of that family, in which they are sister to Perrottetia and Mortonia. The latter two genera, as well as the early-derived Quet-zalia, are somewhat anomalous among Celas-traceae in lacking an aril in favour of a sarcotesta, and partly in possessing scalariform vessel perforations. For the time being it seems therefore justified to retain family status for Parnassiaceae, as suggested by Simmons in his contribution to this volume. As a result of Simmons’ (2001a, 2001b) analysis, Celastraceae are now re-circumscribed to comprise the genera Brexia, Canotia, Plagiopteron, Siphonodon, Stackhousiaceae and Hippocrateaceae, all of which at one time or another had been related to Celastraceae, and all of which have now been shown to be nested within that family.