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The plant megafossil genus Linguifolium Arber 1917 is chiefly known from the Middle and Upper Triassic of Gondwana. The range of Linguifolium extended beyond Gondwana by the Late Triassic, persisting there through the earliest Jurassic (Hettangian). The parent plants probably grew in a well-watered, canopied environment. Diagnoses of the genus and four of its species - Linguifolium tenison-woodsii (Shirley 1898) Retallack 1980, L. waitakiense Bell in Bell et al. 1956, L. parvum Holmes & Anderson in Holmes et al. 2010, and L. steinmannii (Solms-Laubach 1899) Arber 1917 - are emended with particular reference to venation and leaf morphology; consequently, the stratigraphic ranges of the species have been more precisely defined. Coalescent venation has previously been reported in some species of Linguifolium and is identified in new material described herein. Although the vast majority of specimens assigned to the genus are from the Upper Triassic, none shows coalescent venation. This character is entirely restricted to the Middle Triassic, in particular to two species: L. waitakiense and L. parvum. Linguifolium tenison-woodsii is restricted to the Carnian-lowermost Norian of Australia and South Africa and is recorded here for the first time from the Tarong Basin (upper Carnian), Queensland. Confusion regarding assignment of specimens to this species from the Middle Jurassic of Queensland is resolved.

The conifer genus Palissya is reviewed giving special attention to assessing the reliability of Gondwanan material referred to this genus. The collection localities of Australasian specimens are mapped on palaeogeographic reconstructions of Eastern Gondwana at relevant times between 179 Ma and 119 Ma. Australasian and other Gondwanan material previously referred to Palissya is considered to differ substantially from the generic diagnosis. Specimens from the Toarcian of Australasia are shown to be allied to Knezourocarpon; this genus is only known from the Toarcian of eastern Australia. Middle Jurassic–Lower Cretaceous Australasian specimens previously referred to Palissya are likely allied to the Knezourocarponaceae fam. nov. The higher taxonomic affinity of this family is unknown but broadly, its structure is suggestive of ginkgoalean or pteridospermous affiliation. Southern hemisphere specimens were probably catkin-like and megascopically very different from the northern hemisphere Palissya and the two groups are unlikely to be closely related. Consequently, genuine Palissya cones and foliage appear to be restricted to the Rhaetian–Lower Jurassic of the northern hemisphere.

Ediea homevalensis H. Nishida, Kudo, Pigg & Rigby gen. et sp. nov. is proposed for permineralized pollen-bearing structures from the Late Permian Homevale Station locality of the Bowen Basin, Queensland, Australia. The taxon represents unisexual fertile shoots bearing helically arranged leaves on a central axis. The more apical leaves are fertile microsporophylls bearing a pair of multi-branched stalks on their adaxial surfaces that each supports a cluster of terminally borne pollen sacs. Proximal to the fertile leaves there are several rows of sterile scale-like leaves. The pollen sacs (microsporangia) have thickened and dark, striate walls that are typical of the Arberiella type found in most pollen organs presumed to be of glossopterid affinity. An examination of pollen organs at several developmental stages, including those containing in situ pollen of the Protohaploxypinus type, provides the basis for a detailed analysis of these types of structures, which bear similarities to both compression/impression Eretmonia-type glossopterid microsporangiate organs and permineralized Eretmonia macloughlinii from Antarctica. These fossils demonstrate that at least some Late Permian pollen organs were simple microsporophyll-bearing shoot systems and not borne directly on Glossopteris leaves.

In his “abstract motif” notebook, Escher investigated a tiling of the plane by congruent non-regular hexagons, as shown in Fig. 1. He found this tiling in an article by F. Haag [1]; more details can be found in [2] and [3, p. 90]. This tiling can be used to give very simple and elegant proofs of some well known theorems in triangle geometry.

The now-extinct plant Glossopteris that dominated the Southern Hemisphere (Gondwana) during the Permian period serves as early evidence of continental drift1,2, and may be ancestral to the group of seed plants known as angiosperms3. Here we describe a 250-million-year-old fossil from Homevale in Queensland, Australia, of anatomically preserved pollen tubes and swimming male gametes from Glossopteris. The discovery of this simple reproductive system in Glossopteris has implications for its phylogenetic relationships with extant groups of seed plants (conifers and flowering plants, for example) and for the evolution of pollination biology in general.

We describe details of anatomically preserved fossil glossopterid ovules from the Late Permian of Queensland, Australia, that contain several pollen tubes at various stages of releasing flagellated sperm. Each sperm is approximately 12.7 microm long and 13.9 microm wide, with a conspicuous spiral structure comprised of a series of dots that resemble the position of basal bodies of flagella aligned along the multilayered structure (MLS). This configuration is similar to the helically arranged flagella in the sperm of cycads, Ginkgo, and many pteridophytes. However, the motile gametes of Glossopteris are considerably smaller than those of Ginkgo and cycads, and more similar in size, number of basal bodies, and number of gyres in their helix to pteridophyte forms. Glossopteris thus shares the intermediate stage of motile male gamete formation and apparently that of haustorial pollen tubes with cycads and Ginkgo.