The Adiantum gracile group of Brazil and adjacent Bolivia is a natural group distinguishable from A. tetraphyllum and related species. We provide a key to the group and describe two new Brazilian species belonging to the group, A. cinnamomeum and A. dawsonii.

A hybrid woodfern, Dryopteris carthusiana × goldiana, is described and named from a specimen (at DUKE) collected in Monkton, Vermont in 1937. This is the first reliable report of this hybrid. The report is based on morphology of the specimen; no living plants have been found for cytological study. Previous reports of this hybrid combination are excluded.

We conducted a systematic revision of the genus Loxsomopsis H. Christ (Loxomataceae) based on 99 herbarium sheets representing about 52 separate gatherings. Many morphological characters varied considerably, but as much of this variation was found within individual collections it was of little taxonomic relevance. Characters that varied between specimens but remained roughly constant within individual gatherings included the pubescence of lamina, petiole, and sorus, hair size and coloration, presence or absence of glaucous layers on the lamina surface, and spore surface structure. However, we found no correlation in the occurrence of two or more of these characters and were unable to morphologically define discrete species within the genus. Thus, we consider Loxsomopsis to include one variable species, L. pearcei (Baker) Maxon. The morphological variation is probably the result of the distribution of the species in small, isolated populations in ephemeral early successional habitats, leading to continuous population extinction and establishment of new population based on few propagules. Notes on ecology and distribution, full taxonomy, and specimen citations are provided.

The Australian tree fern Sphaeropteris cooperi is an invasive species in Hawaiian wet forests where it displaces Cibotium, the dominant native Hawaiian tree fern, where they co-occur. This study was undertaken in order to assess the relative growth rates and reproductive potential of S. cooperi and the native Cibotium species. Field measurements of growth rates, fertile frond production and leaf traits were made monthly over the course of one year. Sphaeropteris cooperi had a significantly higher growth rate, both in terms of height increase and frond production, and maintained four times more fronds than the native Cibotium species. The mean annual height increase of the invasive tree fern was 15 cm compared to 2 to 3 cm for the native tree ferns. The leaf mass per area of S. cooperi was significantly lower than that of the native Cibotium species, and the leaf life span was significantly shorter, suggesting that the cost of construction of the invasive species' fronds was relatively low. Sphaeropteris cooperi also produced significantly more fertile fronds per month than the native tree ferns. These differences in life history characteristics may help explain the rapid spread and success of S. cooperi in Hawaii.