A new species, Lellingeria cantarensis, is described from the cloud forests of Cerro Jefe, an isolated mountain peak in central Panama known for its high levels of endemism and species diversity. It appears most similar to L. kaieteura and L. epiphytica, both of which also have dorsiventral rhizomes, clathrate rhizome scales with ciliate margins and abaxial hairs on the rachis. The new species is distinct from those two species, and from all other congeners, by its small laminae (less than 6 cm long), truncate laminar base, and the abaxial side of rachis is densely pubescent. Lellingeria subimpressa is also similar to L. cantarensis but it differs by having a glabrous rachis. None of the similar species are sympatric with L. cantarensis; they are restricted to Costa Rica, South America, or Caribbean Islands. A phylogenetic analysis using five plastid markers and 94 other grammitid taxa confirms the new species as sister to the Lellingeria suprasculpta clade with strong support. Lellingeria cantarensis is known only from the type and one additional collection from the type locality, and it is one of ten Lellingeria species found in Panama; it is also the only endemic Lellingeria in the country. We also provide a key to the species that occur in Panama and neighboring Costa Rica. With the addition of this new species, the total number of Lellingeria species becomes 51 worldwide.

Isoëtes cangae and Isoëtes serracarajensis (Isoetaceae) are species endemic to Carajás (Pará State, Brazil) that grow on iron-rich substrates of the Amazon basin under a seasonal rainfall regime. In addition to a few distinctive morphological traits, the species differ in terms of habitat and geographical distribution. The influence of the seasonality and habitat characteristics on quillwort morphology is poorly understood. To assess this influence, specimens from one population of I. cangae, and four populations of I. serracarajensis, were sampled in dry and rainy seasons to investigate variation among vegetative and reproductive characters. The megasporangium color, megaspore ornamentation, alae length, velum length and coverage (%), morphometry of sporangial wall cells, and polar/equatorial diameter ratio of megaspores provide consistent characters for species delimitation. The presence of stomata in I. serracarajensis is a new discovery and is related to its amphibious habit. Some characters that have been used in Isoëtes species descriptions, such as the number of leaves, leaf length, sporangium size, number of megaspores, and megaspore diameter were found to be variable. The current findings provide further information on the biology of the species and show the influence of seasonality and habitat characteristics on the morphological diversity of these lycophytes.

Sporangiasters are an uncommon type of paraphyses, occurring in a handful of leptosporangiate fern genera. We report sporangiasters in Parablechnum nesophilum, which is their first recorded occurrence in the Blechnaceae. We provide evidence of their homology to sporangia and discuss their functional significance. The presence of sporangiasters in P. nesophilum is surprising because the species has a well-developed indusium, and paraphyses are generally most common in exindusiate ferns. We surmise that these sporangiasters act as a second stage of protection for the developing sporangia after the indusium retracts. Alternatively, it is possible that sporangiasters may influence the vagility of spores by inhibiting dehiscence and limiting the ability of the annulus to disperse its spores.

Histiopteris incisa (Dennstaedtiaceae) is one of the most cosmopolitan species among the leptosporangiate ferns. Based on sequences of the chloroplast rbcL gene, we recognize two lineages within H. incisa, and these differ in scale and leaf morphology. This suggests that at least two evolutionarily distinct species are contained within present circumscriptions of H. incisa.