Phylogeny and Character Evolution of the Neotropical Fern Genus Cyclodium (Dryopteridaceae)

Abstract— Cyclodium is a neotropical fern genus with 13 species, most of them distributed in the Amazonian lowlands, particularly in the Guianan region and along the border with the Andes. It belongs to the polybotryoid clade of Dryopteridaceae, being unique within this clade by a combination of characters related to rhizome growth, leaf dimorphism, anastomosing venation, and peltate indusia. Here we present a molecular phylogenetic hypothesis for Cyclodium resulting from Bayesian and maximum likelihood analyses, using molecular sequences of five plastid markers. We also map 12 morphological characters and habit onto the resulting trees. Our results support Cyclodium as monophyletic and sister to Polybotrya. The presence of peltate indusia is the main character distinguishing Cyclodium. Our results also suggest that plesiomorphic conditions in Cyclodium are free venation (vs. anastomosing), creeping rhizomes (vs. erect or decumbent), highly dissected laminae (vs. 1-pinnate), monomorphic sterile and fertile fronds (vs. dimorphic), and pinnatifid apices (vs. conform).

Evolution of floral characters and biogeography of Heloniadeae (Melanthiaceae): an example of breeding system shifts with inflorescence change

Heloniadeae (Melanthiaceae) presents an East Asia–North America disjunct distribution. Different molecular and morphological data nevertheless support the tribe as a monophyletic group. However, their phylogenetic relationships and biogeographic history, together with the character evolution, are not clear. Therefore, we constructed a Bayesian phylogenetic tree for Heloniadeae using cpDNA and inferred the historical biogeography and floral character evolution. The results revealed that Heloniadeae was distributed in high-latitudes of East Asia and North America, originating since 22.2 mya. The East Asia clade migrated into southwest China, and subsequently colonized the Korean Peninsula, Taiwan, the Ryukyus, and spread northward to Japan and southern Sakhalin. The evolution of the inflorescence and number of flowers were phylogenetically conserved, associated with the historical biogeography of Heloniadeae. The inflorescences transferred from raceme to sub-umbel, and the number of flowers decreased during the dispersal process, which may be accompanied by changes in the breeding system. Besides, the anthesis period was more affected by the habitat environment than phylogenetic constraints. The flowering temperature of was below 20 °C in most species, except H. kawanoi. Such a low temperature might not be conductive to pollinator activities, but it could be compensated by sustaining seed production with long-lasting flowers.

Nutlet micromorphology and character evolution of Lappula species (Boraginaceae) and its systematic implications

Background The macro/micro-morphology of nutlets in 11 species (and 22 accessions) of the Boraginaceae family was investigated using stereomicroscope and scanning electron microscopy to evaluate the taxonomic relevance of the traits. To evaluate the phylogenetic significance of the character evolution, phylogenetic analysis was carried out by comparing available DNA sequence data from GenBank with selected original nutlet data. Results The Rochelieae nutlets' shape varied from ovoid (ovoid, ovoid-triangular, and ovoid-rectangular) to pyramid. Six major patterns were recognized based on the nutlet ultrastructure characters. Rocheliae is characterized by a transition from “without appendage” to “with tubercles and prickles” on the nutlet disk, and also via a shift from “lack of prickles” to “glossy prickles”. Conclusions The results show that the nutlet ultrastructure pattern of Rochelieae is systematically informative at the genus level, but not at the species level. Findings demonstrated that glochid is not an ancestral trait but is a synapomorphy and the transition to this trait occurred in the genus Lappula. The close boundary of nutlet microstructures between L. barbata and L. microcarpa has been discussed.