Rare and peculiar hornworts: Notothylas orbicularis and N. javanica (Notothyladaceae), new genus and species records for Australia

Abstract

The hornwort genus Notothylas is newly recorded for Australia. Detailed descriptions, illustrations and a key to the two known species, N. orbicularis and N. javanica are provided. A peculiar phenomenon involving presentation of the sporophyte on the ventral (rather than the dorsal) surface of the gametophyte, known only in Australian populations of Notothylas, is reported and discussed.