104 PLANT HYBRIDIZATION BEFORE MENDEL 



15. The Experiments of Thomas Laxton. 



In 1872, Thomas Laxton published, in the Journal of the 

 Royal Horticultural Society, results of hybridization experiments, 

 entitled "Notes on Some Changes and Variations in the Offspring 

 of Cross-fertilized Peas" (4b), which have several points of dis- 

 tinct interest: first, in that the fact of dominance in color and 

 form of the seeds was brought out; second, from the fact that, 

 to a certain limited extent, a statement of numerical results was 

 attempted. The results in neither of these were sufficient to con- 

 stitute a scientific experiment, but the work as a whole gives 

 evidence of care, close observation, and some thought. Among 

 the several reported pieces of experimental work with peas before 

 Mendel, Laxton's is perhaps to be commended as being more 

 nearly of an exact nature, and is also interesting from the fact 

 that it constitutes the last experimental work in the hybridization 

 of peas, published before the final re-appearance of Mendel's 

 papers themselves. Laxton says : 



"since the year 1858, I have been carrying on continued and successive 

 courses of experiments in cross-fertilizing the cultivated varieties of the 

 Pea, partly with a view to produce improved characters, and partly for 

 the purpose of noting the results of artificial impregnation on a genus 

 of plants, which, although not absolutely beyond the reach of accidental 

 cross-fertilization, is, for most practical purposes, sufficiently free from 

 it to make the changes produced by artificial impregnation approximately 

 reliable, at all events more so than in the majority of genera." (4b, p. 10.) 



Laxton, at the time of his experiments, was not aware of the 

 work of Knight with peas some fifty years previously. 



In 1866, a cross was made upon an early, white-flowered variety, 

 known as "Ringleader," with round, white seeds, and growing to 

 a height of about 2^ feet, by a purple-flowered variety known as 

 "Maple," with slightly indented seeds, and taller than the pre- 

 ceding. This produced one pod, containing five round, white peas 

 like those of the female parent, the ordinary result. The seeds of 

 the parent variety known as "Maple" are not described, but the 

 results leave it to be inferred that the seed-coat color was grayish- 

 purple, whence the name. In 1867, the five seeds of the F^ gen- 

 eration produced "tall, purple-flowered, purplish-stemmed" plants, 

 and the seeds, "with few exceptions," had "maple or brownish- 

 streaked seed-coats." The remainder are reported with "entirely 

 violet or deep purple-colored envelopes" (the ordinary dominant 

 for seed-coat color in the F^). The dominance of roundness in 



