The Following paragraph is from preface of this book :
" The identification of plants mentioned in the Natural History is a difficult matter. Pliny was not a botanist, but derived his information from books, which were often read aloud to him while he took notes, and not studied at leisure. Naturally he made mistakes due to misunderstandings. Pliny's authorities again were sometimes inadequate or confused or even wrong. In addition to the difficulties caused by positive error, there is also another one due to the fact that the same name was often given to more than one plant, and the same plant was often called by more than one name. Accordingly even a trained botanist hesitates at times to give with any confidence the modern equivalent of an ancient name in some particular context. Sometimes, of course, there is no reasonable doubt; rosa is rose, and cepa onion. Often, however, even when certain that a Latin or Greek name is generally equivalent to an English one, the botanist is not sure that a variety included by Pliny, or Theophrastus, under the former should also be included under the latter. The degree of doubt may vary from a moral certainty to a slight suspicion. Typical difficulties are those facing the translator when he has to render into English asparagus, hyacinthus and strychnos. To keep the Latin name always would be consistent, but cumbersome and pedantic. It seems better to give the English name when the risk of error is slight, but to keep the Latin when the risk is great. An index of plants, with probable or possible identifications, should give most readers the information they require. But some inconsistencies and uncertainties are inevitable."
Which is "former" and "latter" in " Often, however, even when certain that a Latin or Greek name is generally equivalent to an English one, the botanist is not sure that a variety included by Pliny, or Theophrastus, under the former should also be included under the latter. "
I understand it (1) former (Latin or Greek) variety under latter(English) or (2) former(Pliny) variety under latter( Theophrastus ).