Article: Jurassic araucarian cone from southern England
A well-preserved araucarian cone measuring 4.5 x 5.0 cm is described from Jurassic age limestone from near Osmington Mills, Dorset. Four pieces of cone material representing a single specimen are somewhat flattened and lignitic, with intact seed and cone-scale tissues. The cone axis and bract apophyses are replaced with a calcitic matrix. Helically arranged cone-scale complexes with a prominent ligular sulcus surround a wide pith. One recurved wingless ovule 0.8 cm long is deeply sunken into the cone-scale tissue. Seed integuments are relatively mature and contain three distinct layers the most prominent of which is the sclerotesta constructed of interlocking zig-zag sclereids. The nucellus, in some cases still cellular, is free from the integuments except at the chalaza and has the characteristic wavy apex common to extant araucarians at a comparable developmental stage. A well-developed vascular system like that in Araucaria bidwillii Hooker is present near the seed chalaza. Cellular megagametophyte and embryos are present within some seeds. The specimen is described as a new species, A. brownii sp. nov. in which the cone structure most closely resembles that of the section Bunya of the genus Araucaria. This discovery extends the range of this section to the Northern Hemisphere during the Mesozoic.