Compressed specimens of the fern Osmunda are described from the Triassic of the Allan Hills, Antarctica. The specimens consist of a once pinnate, deeply pinnatifid fertile frond as well as several sterile specimens. Six pinnae are present on the partial fertile rachis, with two sterile pinnae above four fertile pinnae. Both sterile and fertile specimens are virtually identical to the modern species Osmunda claytoniana. Entire fronds are fragmentary; the longest is 21 cm in length. Sterile pinnae are alternate and deeply pinnatifid, with slightly toothed pinnules and dichotomous venation. Fertile pinnae are 1-1.3 cm long, once pinnate, and lack vegetative lamina. Sporangia are clustered, each 300-375 um in diameter, and possess a transverse annulus 6-8 cells long; dehiscence is by a vertical slit. Fronds arise from a rhizome 4 cm long by 1 cm wide; two croziers are present on the rhizome. Two frond segments up to 6 cm long and three deeply pinnatifid pinnae are present on the uppermost part of one rachis. Pinnules are ~4 mm long and 2-3 mm wide. The presence of this Osmunda species in the Triassic demonstrates stasis of frond morphology, both fertile and vegetative, for the genus.

Megaspore and microspore massulae of Paleoazolla patagonica gen. et sp. nov. are described from the Upper Cretaceous of La Colonia Formation, Chubut Province, Argentina. The new fern possesses megaspore complexes with three to four glochidiate floats attached directly to the megaspore; a columella-like structure appears to be absent. The megaspore wall consists of a two-layered exine that is smooth to irregularly perforate, a two-layered perine with a spongy, densely packed endoperine, and a loosely organized exoperine. Infrafilosum hairs cover the exoperine. Microspore massulae are irregular in size and shape and bear multibarbed glochidia that generally have anchor-shaped tips. A comparison with other azollaceous and salviniaceous genera, particularly Azolla, is provided, together with a discussion of some evolutionary trends within the family.

Arbuscular mycorrhizae are the most ubiquitous of mycorrhizal fungi, that have formed mutualistic relationships with virtually almost all major groups of vascular plants. Five genera of arbuscular endomycorrhizal fungi are currently delineated, but fossil arbuscular mycorrhizae have been allied with only two, Glomus and Sclerocystis. A Triassic arbuscular mycorrhiza described inhabiting the roots of Antarcticycas was originally allied with Glomus. It is now known to be a mixed colony comprised of fungi attributable to the suborders Glomineae and Gigasporineae of the Glomales, described as two new species. The fossil Gigasporinean mycorrhiza is characterized by irregularly swollen intercellular and intracellular hyphae that are coiled extensively within the cells. Arbuscules have thick trunks and narrow branches. In the Glominean form, hyphal diameter is more uniform,with coiling rarely present. Arbuscules have thin trunks and fine branches. Vesicles may be lateral or terminal. Spores are not present; therefore, the probability of more than one species of each suborder being represented cannot be conclusively demonstrated. This provides the first fossil representative of the Gigasporineae and supports current rDNA estimates of the age of the lineage. Moreover, it is the first reported instance of a mixed colony of arbuscular endomycorrhizae in the fossil record.