How unknown was Mendel's paper?

Abstract

The alumni association of a university once published a list of graduates whose addresses it had been unable to discover. A journalist looked in the telephone directory of the city where the university was located and found a large proportion of the names listed there, with of course their addresses and telephone numbers. This incident came to my mind when I saw on the reference shelves of a botanical library a copy of Guide to the Literature of Botany by Benjamin Daydon Jackson, secretary of the Linnean Society of London,' published in 1881. This is a bibliography containing selected titles classified by subject. It is a standard work found, I believe, in most botanical libraries, at any rate in English-speaking countries. It was described as still useful in 1928, the year after Jackson's death at the age of eighty-one,2 and as indispensable in 1964, when a facsimile edition was issued.3 There seemed little likelihood that it contained a reference to Mendel's "Versuche Uber Pflanzen-Hybriden,"4 for such a reference would surely have been discovered and reported by now. Still, the possibility, however small, seemed worth the trouble of opening the book and looking. And, sure enough, in the index was the entry "Mendel, 100"; and on page 100 wasa section headed "Hybridization" containing thirteen items, including