A Study of Kansas Cottonwoods

An attempt to standardize the characters of Populus deltoides Marsh. and P. Sargentii Dode led back to the earliest taxonomists without satisfactory results. Collection of Poplus specimens was made throughout much of Kansas and at a few stations as far east as Vermont. Scatter diagrams and hybrid indices charts of these proved inconclusive. The cottonwoods in woodlots planted under the Timber Culture Act of 1873 have provided a non-indigenous, though 93% Kansan, gene pool and thus complicated the findings. The author concludes that either introgression has made taxonomic conclusions concerning these two species difficult in Kansas or that cottonwoods are so genetically plastic that Populus deltoides and P. Sargentii should be considered one species. Cytological study or chemotaxonomy are indicated.