Answers CD’s questions about plants common to U. S. and Britain and their distribution in Europe.

Variability of agrarian weeds.

Evidence relevant to E. Forbes’s land-bridge theory.

Do the plants that are common to Europe and North America nearly all live north of the Arctic Circle? CD bases his question on HCW’s "capital" comparison between relations of Europe to North America and Europe to E. Asia if the intervening land had been submerged. CD has been led to speculate that in the mid-Pliocene the organisms now living in middle Europe and northern U. S. lived within the Arctic Circle. Subsequent movements of this flora with advance and retreat of glaciers would explain present distribution better than Forbes’s vast submergences.

Conveys [? J. T. I. Boswell-]Syme’s opinion of variability of agrarian weeds and ranges of species common to U. S. and W. Europe. The Hispano-Hibernian connection.

Greatly interested in CD’s experiments with seeds in salt water [see "Action of sea-water on seeds", Collected papers 1: 264–73]. Believes CD exaggerates the force of the objection, against migration, that seeds tend to sink.

Discusses means of seed transport.

Considers the difficulty of deciding which, if any, botanical species are real.

Responds to CD’s query on Subularia and Limosella. There are discrepancies among authorities on whether Subularia flowers out of water. Limosella certainly flowers out of water.

Notes on the comparative rarity of intermediate forms between species, and the varying relationships those forms may have to one or both species between which they are intermediate.