Siphocampylus

Abstract:  Premise of the study: The species-rich Neotropical genera Centropogon , Burmeistera , and Siphocampylus represent more than half of the ~1200 species in the subfamily Lobelioideae (Campanulaceae). They exhibit remarkable morphological variation in fl oral morphology and habit. Limited taxon sampling and phylogenetic resolution, however, obscures our understanding of relationships between and within these genera and underscores our uncertainty of the systematic value of fruit type as a major diagnostic character.  Methods: We inferred a phylogeny from fi ve plastid DNA regions ( rpl32 - trnL , ndhF - rpl32 , rps16 - trnK , trnG - trnG - trns , rbcL ) using maximum-likelihood and Bayesian inference. Ancestral character reconstructions were applied to infer patterns of fruit evolution.  Key results: Our results demonstrate that the majority of species in the genera Centropogon , Burmeistera , and Siphocampylus together form a primarily mainland Neotropical clade, collectively termed the “centropogonids.” Caribbean Siphocampylus , however, group with other Caribbean lobelioid species. We fihigh support for the monophyly of Burmeistera and the polyphyly of Centropogon and mainland Siphocampylus . The ancestral fruit type of the centropogonids is a capsule; berries have evolved independently multiple times.  Conclusions: Our plastid phylogeny greatly improves the phylogenetic resolution within Neotropical Lobelioideae and highlights the need for taxonomic revisions in the subfamily. Inference of ancestral character states identifi es a dynamic pattern of fruit evolution within the centropogonids, emphasizing the diffi culty of diagnosing broad taxonomic groups on the basis of fruit type. Finally, we identify that the centropogonids, Lysipomia , and Lobelia section Tupa form a Pan-Andean radiation with broad habitat diversity. This clade is a prime candidate for investigations of Neotropical biogeography and morphological evolution.

Abstract: A 3.7 kilobase region of chloroplast DNA that includes atpB, rbcL, and their intergenic spacer was sequenced in 61 samples from 45 species of South American Lobeliaceae plus two outgroup samples from Australia. A clade of four hexaploid Lobelia species from Chile is sister to a clade comprising Lysipomia, Siphocampylus, Centropogon, and Burmeistera. Lysipomia is a monophyletic group of small cushion-forming plants endemic to the high Andes, and is sister to the clade comprising the remaining three shrubby genera, which are most diverse in the Andes, but also extend to Central America, Mexico, and the West Indies. Siphocampylus has capsular fruit and is inferred to be paraphyletic relative to fleshy-fruited Centropogon and Burmeistera, but fleshy fruits have evidently evolved repeatedly, making Centropogon polyphyletiC. Burmeistera is primarily bat-pollinated and monophyletic, having evolved from one group of species in Centropogon. The phylogenetic relationships within Burmeistera indicate that t...

Abstract: Recent surveys of seed coat morphology in Lobelioideae (Campanulaceae) have demonstrated the systematic utility of such data in the subfamily and led to a revision of the supraspecific classification ofLobelia. Expanding upon these studies, we examined via scanning electron microscopy 41 seed accessions, emphasizing lobelioid genera in which only one or no species had been examined. Most conformed to previously described testal patterns. However, five species of the endemic Hawaiian genus Cyanea, comprising the molecularly defined Hardyi Clade, had a unique testal pattern (here termed Type F), characterized by laterally compressed, almost linear, areoles with rounded, knob-like protuberances on the radial walls at opposite ends. This offered a convenient synapomorphy for recognition of a clade originally defined on a molecular basis. A second unique testal pattern was found in the related Hawaiian endemics Brighamia and Delissea, thus supporting their close relationship. In this type (here termed Type G), the seed coat is irregularly wrinkled (rugose), creating broad, rounded ridges that run more-or-less perpendicular to the long axis of the seed and thus to the long axis of the testal cells. Seed coat morphology also supported the monophyly of all 124 species of Hawaiian Lobelioideae and their probable derivation from Asian species of Lobelia subg. Tupa. Additional studies supported close relationships between (1) the neotropical genera Centropogon and Siphocampylus; (2) the western American genera Legenere and Downingia; and (3) Jamaican Hippobroma and Lobelia sect. Tylomium, a group endemic to the West Indies.

Abstract: Burmeistera, Centropogon, and Siphocampylus together comprise more than 500 species endemic to the Neotropics, Current knowledge of these genera is unsatisfactory, with much diversity yet to be described. Over the past seven years, one out of every 28 specimens received for identification has represented a new species, many characterized by unique or unusual character states. Siphocampylus smilax (Bolivia) is unique in the genus in its parallelodromous leaf venation and extra-floral nectaries. Centropogon dianae (Peru) cannot be accommodated in any recognized infrageneric taxon, and a new section, Centropogon sect. Niveopsis, is proposed for it. The flowers of C. steinii (Ecuador) are the smallest known in the genus, while C. connatilobatus (Venezuela) is the first species to combine arbusculiform pubescence and connate calyx lobes. Burmeistera venezuelensis is only the second species of the genus known to occur in Venezuela and the first to be endemic; similarly, Centropogon wilburii is only the third species of Centropogon known from Mexico and the first to be endemic to that country. Additional novelties are also described.