Further evidence for the hybrid status of the Brazilian native fern Hypolepis ×paulistana (Dennstaedtiaceae).

Hypolepis ×paulistana was described in 2016 as a putative hybrid, known from a single gathering. The hybrid status of these plants was based solely on the intermediate morphology of the sporophyte, when compared to its presumed parent species. These were thought to be H. stolonifera and H. rugosula, but, H. rigescens (Kunze) T. Moore could not be explicitly ruled out either. In the present work, we tested the hybrid status of Hypolepis ×paulistana adding palynological evidence and by using chloroplast sequences to unambiguously identify the maternal progenitor of the species. We find that sporangia of Hypolepis ×paulistana contain both well-formed spores, as well as spores with morphological and developmental anomalies. The size of the regular spores and the abnormal spores suggest that H. ×paulistana is likely a diploid, and probably infertile hybrid. The ornamentation of the regular spores of H. ×paulistana is similar to that of H. stolonifera. The chloroplast sequences of H. ×paulistana are identical to those of H. stolonifera, as well as their sister position within the global phylogeny of the genus. Thus, we provide new evidence for the hybrid status of H. ×paulistana, and we corroborate the earlier finding that H. stolonifera is the maternal parent.

New insights into the evolution of the fern family Dennstaedtiaceae from an expanded molecular phylogeny and morphological analysis.

Dennstaedtiaceae has 270 species, a worldwide distribution, and an edge-colonizing habit that is unusual among ferns. Aneuploidy, polyploidy, and hybrids are common in the family. Combining morphology, anatomy, chromosome number, and geographical distributions with our newly generated molecular phylogeny, we provide new insights into the evolution of the family. We paid special attention to Hypolepis. Our molecular dataset of five cpDNA markers is the most comprehensive to date, comprising 72 species (and a total of 98 taxa), of which 33 are Hypolepis (45 taxa). We also generated divergence-time estimates through BEAST with four fossil calibrations. We recovered three sub-families in Dennstaedtiaceae: Monachosoroideae (monogeneric), Dennstaedtioideae, and Hypolepidoideae. Monachosoroideae has a chromosome base number of x = 28; Hypolepidoideae of x = 26; while in Dennstaedtioideae this is still obscure, with different numbers ranging from 30 to 47. Dennstaedtioideae genera require re-circumscriptions because Dennstaedtia is polyphyletic. In Hypolepidoideae, the six genera are monophyletic. Within Hypolepis, seven geographically distinct clades were recovered; but we found no strong morphological characters to define them. Within the family, the long-creeping rhizome evolved with a change in habit: from shade-tolerant to edge-colonizers, to thicket-formers. Short or extremely large leaves are derived conditions. Sorus shape and position, glandular hairs, and prickles are homoplastic. Hybridization/allotetraploidy in Hypolepis can be suggested by the combined data. In our phylogenetic hypothesis, Dennstaedtiaceae originated around 135 Ma, with the split of Monachosoroideae around 94 Ma, and the split between Dennstaedtioideae/Hypolepidoideae around 78 Ma. All extant genera are inferred to be relatively young. Hypolepis started to diversify around 10 Ma, and it probably originated in east Asia and/or Oceania. Hypolepis reached the Neotropics twice: through elements of the Hypolepis rugosula clade (which originated at 7 Ma), and through the ancestor of the Neotropical clade, which originated at 3.1 Ma and was prickly.

Hiya: A new genus segregated from Hypolepis in the fern family Dennstaedtiaceae, based on phylogenetic evidence and character evolution.

The relationship of Hypolepis brooksiae, H. nigrescens, and H. scabristipes to the remainder of Hypolepis (Dennstaedtiaceae) has been questioned by previous authors based on their unique combination of morphological characters and different base chromosome number. Using four chloroplast genes including rbcL, atpA, rpL6, and rps4-trnS intergenic spacer (IGS) from 32 samples, representing 24 species of Dennstaedtiaceae, we recovered a clade comprising H. brooksiae and H. nigrescens, distinct from the remaining species of Hypolepis. This clade is resolved as sister to the clade comprising Blotiella, Paesia and Histiopteris. We reconstructed ancestral states of 16 morphological characters and found that this clade is distinguished by indeterminate, scandent leaves exhibiting rhythmic growth, provided with recurved black-tipped prickles, and stipule-like pinnules that protect the emerging crosier and pinnae departures, rachis-costa architecture where the adaxial sulcus is confluent with the next lower order, and a base chromosome number of x = 29. In light of this molecular and morphological evidence, we describe a new genus, Hiya, and provide nomenclatural combinations to accommodate the three known species segregated from Hypolepis: Hiya brooksiae, Hiya nigrescens, and Hiya scabristipes.

A new Inocyclus species (Parmulariaceae) on the neotropical fern Pleopeltis astrolepis.

During a survey for fungal pathogens associated with ferns in Brazil, a tar spot-causing fungus was found on fronds of Pleopeltis astrolepis. This was recognised as belonging to Inocyclus (Parmulariaceae). After comparison with other species in the genus, it was concluded that the fungus on P. astrolepis is a new species, described here as Inocyclus angularis sp. nov.

Induction of leafy galls in Acacia mearnsii De Wild seedlings infected by Rhodococcus fascians

Plantas recém germinadas de acácia negra (Acacia mearnsii De Wild.) foram inoculadas com a bactéria Rhodococcus fascians e cultivadas in vitro. Galhas cobertas por folhas apareceram na altura do nó cotiledonar em 75% das plantas infectadas. As galhas foram separadas das plantas e cultivadas num meio de cultura contendo os sais do meio MS (Murashige e Skoog, 1962) reduzidos a 3/4, as vitaminas do mesmo meio, 2% de sacarose e um antibiótico (cefalotina), adicionado ou não de 0,2% de carvão ativo. Estudos histológicos realizados entre o sexto e o vigésimo segundo dia depois da inoculação, revelaram a presença de centros meristemáticos novos, primeiro nas regiões axilares, em seguida nos pecíolos e limbos dos folíolos ao redor do meristema apical. Aproximadamente 37% das galhas desenvolveram um broto na presença de cefalotina.