Modern molecular phylogenetic studies of the Pteridaceae have recognized a well supported cheilanthoid clade that includes four major subclades: myriopteroids, pellaeoids, hemionitidoids and notholaenoids. Many of the morphological characters used in delimitation of the cheilanthoid lineages and genera appear to be the result of convergent evolution, a result of adaptation to xeric environments. Faced with the apparent lack of sporophytic synapomorphies for the cheilanthoid subclades, farina production by gametophytes has been proposed as a character of possible phylogenetic utility. All the notholaenoid species observed to date produce farina in their gametophytes, but species of the other cheilanthoid clades (pellaeoids, hemionitidoids, and myriopteroids) do not. In this work we provide the first account of farina production in the gametophyte of a non-notholaenoid: two accessions of Argyrochosma nivea from different geographical localities were found to have farina on their gametophytes, suggesting that this gametophytic character is not a synapomorphy for the notholaenoids, and may have had several independent evolutionary origins.

Chagas disease is caused by Trypanosoma cruzi, and is considered a public health problem. The current treatments for this disease are the synthetic drugs nifurtimox and benzonidazol, which are highly toxic. Pityrogramma calomelanos, a plant used in traditional medicine as an astringent, analgesic, anti-hemorrhagic, pectoral depurative, emmenagogue, anti-hypertensive, anti-pyretic and an anti-tussive was tested for antiepimastigote activity in vitro. An ethanol extract and hexane fraction of P. calomelanos was prepared and tested against T. cruzi (CL-B5 clone). The effective concentration capable of killing 50% of parasites (EC₅₀) was 55.26 µg/mL and 73.57 µg/mL for the ethanol extract and hexane fraction, respectively. This is the first record of tripanocidal activity for P. calomelanos. Our results indicate that P. calomelanos could be a source of antiepimastigote natural products with only moderate toxicity toward healthy human cells.

As one of the worst invasive alien plant species in China, Ageratina adenophora has caused serious economic losses and reduced the diversity of native species, possibly due to allelopathic interactions. However, we have little knowledge of its effects on ferns. In Petri dish bioassays, the effects of the aqueous leachates from roots, stems and leaves of A. adenophora on spore germination and gametophyte development of Neocheiropteris palmatopedata were investigated. All leachates inhibited spore germination and rhizoid growth of N. palmatopedata. Furthermore, the inhibitory effects increased with increasing leachate concentrations, and root leachates exhibited the greatest inhibition. Possible inhibitory causes are discussed in the present study. Additionally, the gametophytes of N. palmatopedata treated with the leachates of A. adenophora did not show morphological differences compared with the control. This result differs from previous studies investigating morphological changes in other fern species when associated with A. adenophora. Varying sensitivity of different fern species to the same allelochemicals of A. adenophora may partly be responsible for this difference.

Mycorrhizal fungi form dynamic symbiotic association in the roots of about 80% of the total terrestrial vascular land plants. Among the pteridophytes, mycorrhizal associations are more frequent in the gametophytes than in the sporophytes. Gametophytes of many ferns and lycophytes exhibit obligate mycotrophy. Despite several benefits derived from the mycorrhizal fungi, very little work has been done surveying the distribution and diversity of arbuscular mychorrhizal (AM) fungi in pteridophytes. We intensified our studies in the roots of sporophytes of Christella dentata (Forssk.) Brownsey & Jermy (Thelypteridaceae) to understand the distribution of AM fungi in different parts of the main adventitious root and its lateral branches, along with percent root colonization. We also evaluated spore density of AM fungi in the soil and seasonal variations in the hyphal colonization and formation of vesicles and arbuscules. Root colonization was present in the lateral roots only and not on the main adventitious roots. Percent root colonization also varied in different parts of the lateral roots. The results indicated that root colonization percentage of AM mycorrhizal fungi varies not only by the growth stages of host plants but also by season. Soil spore count was highest in the winter and lowest during the rainy season. In addition to AM fungi, another type of root colonizing fungi, dark septate fungi (DSF) or dark septate endophytes (DSE), has also been recorded in the roots of C. dentata. Dark septate fungi with melanized hyphae and microsclerotia were documented.

The identity of Azolla species in the Kashmir Valley has been confusing, with most populations being reported as Azolla pinnata. Morphological evidence demonstrates that the species introduced to Kashmir is not A. pinnata, but rather Azolla cristata, a new species for the Kashmir Valley and a potentially problematic biological invader.