LIKE PEAS IN A POD: This photographic plate from Raphael Weldon’s 1902 article displays the spectrum of pea color variation as a critique of Gregor Mendel’s binary categorization of yellow and green. Images 1–6 display the color range of pea seeds of the variety Telephone as sorted by Weldon after removing their seed coats. Images 7–12 display a color scale from the pea variety Stratagem with coats removed. Images 13–18 show color variations in the two cotyledons of the same pea (Telephone variety). Images 19–24 display peas in their seed coats, which mask any color differences between cotyledons (19–20 are of the Telephone variety; 21, Telegraph; 22, Stratagem; 23, Pride of the Market; and 24, Early Morn).
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At the turn of the 20th century, Gregor Mendel’s seminal 1866 paper on pea plants and the principles of inheritance resurfaced in the scientific community, thanks to a few intrepid botanists who had arrived at similar conclusions in their own research. Examining the findings reported in Mendel’s long-buried paper, Walter Frank Raphael Weldon, an Oxford University zoologist at the time, found himself embroiled in controversy.
Weldon had excelled at statistically analyzing variations in wild populations of crabs, shrimps, and snails, and was well-equipped to take a measured look at the Mendel mania occurring among his contemporaries. “[Mendel’s work] was very exciting—even potentially holding the key to a new quantitative science of inheritance,” says Gregory Radick, a science historian and philosopher at the University of Leeds. ...
