Gregor Mendel wasn't the only one with an interest in heredity, and he wasn't the first to work with plants. So why were his results almost unknown until 1900 and the rediscovery of the laws of inheritance?
The common assumption is that Mendel was a monk working alone in a scientifically isolated atmosphere. His work was ignored because it was not widely distributed, and he didn't make an effort to promote himself. In actual fact, the reasons are more complex.
Mendel was part of the social and scientific circle of the time. He attended the University of Vienna, and came into contact with many prominent scientists. He had opportunities to travel to and attend scientific conferences. His paper, when published in 1865 in The Proceedings of the Br�nn Natural Science Society, was exchanged with the publications of at least 120 other associations and societies, and was available in many libraries and scientific institutes. In addition, Mendel sent out 40 reprints to some of the most famous botanists at the time.
Through correspondence with another leading botanist, Carl N�geli, Mendel did spark an interest but N�geli was working on hawkweed, a plant that unbeknownst to him reproduced sexually and asexually. N�geli convinced Mendel to do further hybridization experiments with this plant. Mendel was unable to prove his laws of inheritance using hawkweed as a model, and so abandoned the effort. From his letters, Mendel appeared to be a humble person. The fact that he failed with hawkweed would have cast doubt into his mind as to whether his Laws were truly "fundamental" to all living things. N�geli, of course, would see that Mendel's results didn't apply to hawkweed, and so they must be incorrect.
Mendel also did present his data in a way that was atypical for a botanist. The natural sciences were traditionally more of a descriptive one where details were noted for their use in classification purposes. Botanists at the time certainly counted hybrid offspring, but they did so more to note yields than to connect the numbers with trait inheritance. Mendel's mathematical ratio of inheritance was probably not understood by many botanists. Subsequent mentions of Mendel's results usually focused on the hybrids that Mendel made, ignoring the mathematics altogether.
As is often the case in science and in other areas, a topic captures the imagination and overshadows everything else. In the 1860's the hot topic was Charles Darwin's theory of evolution. The controversy generated over that theory made it easy to overlook a pea plant study. Ironically, it was the examination of how variations are inherited during the course of evolution that led to the rediscovery of Mendel's laws in 1900.