Summary

Rows of cells with granular matter following treatment with carbonate of ammonia also found in white and young rootlets of common zonal Pelargonium. Differs slightly from Euphorbia in that 2, 3, 4, or 5 rows often adjoin. CD wrong in supposing that these rows of cells were connected with lacticiferous ducts ("milk-tubes"). Root hairs arise exclusively from rows of cells without brownish granular matter. It appears that certain rows of cells with hairs are absorbent and store matter of some kind. This is a new view of the structure and function of rootlets. Francis Darwin will soon set up the salt solution to make the experiment SHV recommends.