Note 28 — GHARDAIA TO TOUGGOURT.
Reading edition
In the case of annuals the differences in development of the shoot between plants well watered and those with only a meager supply are very striking. In one instance in the Tucson region specimens of Parietaria debilis growing in extreme conditions, one moist and the other arid, varied in length between 39 cm. and 8 mm., or a difference with a ratio of 49 to 1. (Root Habits of Desert Plants, loc. cit.)