Dryandra subg. Diplophragma is an obsolete subgenus within the former genus Dryandra (now Banksia ser. Dryandra). It was first published by Robert Brown in 1830, but was discarded by George Bentham in 1870. It was reinstated with a new circumscription by Alex George in 1996, but was ultimately discarded again in 2007 when Austin Mast and Kevin Thiele sank Dryandra into Banksia. According to Brown Diplographma was first published by Brown in his 1830 Supplementum primum prodromi florae Novae Hollandiae. Brown's arrangement divided Dryandra into three groups according to what Brown perceived to be variations in the number of seed separators. He allowed for these groups to be treated at subgenus or section rank, but they are now treated as having been published as sections. D. sect. Diplophragma was defined as containing a single species, D. bipinnatifida (now Banksia bipinnatifida), which Brown thought contained two seed separators. The epithet Diplophragma is from the Greek diplo ("two") and phragma ("barrier"). It is not clear how Brown came to believe that this species has two seed separators, as it actually has none. The placement and circumscription of D. sect. Diplophragma in Brown's 1830 arrangement may be summarised as follows: Dryandra (now B. ser. Dryandra) Dryandra verae (18 species) D. sect. Diplophragma D. bipinnatifida (now B. bipinnatifida) D. sect. Aphragma (4 species) Hemiclidia (1 species) According to Meissner In 1856, Carl Meissner published a revision of Dryandra. He retained all three of Brown's sections, but added bipinnatifid leaves (that is, leaves that are divided into lobes that are themselves divided) to the defining characters of D. sect. Diplophragma, and included in it the species D. preissii (now Banksia acuminata), which had been published in 1845. The placement and circumscription of D. sect. Diplophragma in Meissner's arrangement thus looks like this: Dryandra (now Banksia ser. Dryandra) D. sect. Eudryandra (8 series, 47 species, 7 varieties) D. sect. Diplophragma D. bipinnatifida (now B. bipinnatifida) D. Preissii (now B. acuminata) D. sect. Aphragma (4 species, 4 varieties) Hemiclidia (1 species) According to Bentham Along with many of Meissner's infrageneric taxa, which were overly reliant on leaf characters, Bentham discarded D. sect. Diplophragma in his 1870 arrangement. Despite having seen only a few seeds, he correctly observed that the characteristics of the fruit upon which Brown based the section were not constant: Bentham also recognised that the two species placed in D. sect. Diplophragma by Meissner are