Vittarioideae worthy of subgeneric rank, while "Rheopteris" had not yet been discovered. "Haplopteris" he explicitly synonymized with "Vittaria" in 1914. Carl Christensen used the name "Vittarioideae" in Verdoorn's "Manual of Pteridology" in 1938, but did not include a description, leaving it nomenclaturally invalid. Ren-Chang Ching raised Vittariaceae to the rank of a family in 1940. The first well-sampled molecular phylogenetic study of the vittarioids was based on the chloroplast gene rbcL. In this study, it was found that the type species of "Monogramma" is embedded in "Haplopteris"; the segregation of "Vaginularia" from "Monogramma" was also supported, as members of "Vaginularia" formed
The Private Life of Plants lead to the prey developing methods of self-defence — from plants growing spikes to insects learning to recognise mimicry. Yet humans can work around all these rules of nature, so Attenborough concludes with a plea to preserve plants, in the interest of self-preservation. In the 2002 documentary "Life on Air", Keith Scholey, the head of the BBC Natural History Unit, relates that he and his team had been wondering about an ecology series that included plants, and found that Attenborough had been thinking along the same lines: "So we went to his house and David, as always, listened to our