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 Variation of Animals and Plants under Domestication spite of the fact that a considerable number of these assumptions are untenable, a part of the theory still remains which must be accepted as fundamental and correct,--in principle at any rate,--not only now but for all time to come. ... presupposing the existence of material particles in the germ which possess the properties of the living being ... I must honestly confess to having mentally resisted this fundamental point of the Darwinian doctrine for a long time." The Variation of Animals and Plants under Domestication The Variation of Animals and Plants under Domestication is a book by Charles Darwin