A Population Study of Spergula arvensis

Publisher Website
Google Scholar
Abstract
Two seed-coat forms (the presence or absence of papillae) and two hairiness forms (medium or densely hairy) of Spergula arvensis are differently distributed through the British Isles, their relative frequencies being correlated with latitude and altitude. The proportions of the non-papillate and densely hairy forms increase with increasing distance from Kent to the north-north-west and also with increasing altitude. A possible explanation is that the diverse forms indicate selective differences. Experiments have been carried out to test this hypothesis and the evidence supports it. The non-papillate form produces a lower proportion of fertile capsules than the papillate form when grown at a high temperature and low humidity. Also the non-papillate seeds germinate more readily than the papillate seeds at low temperatures, whereas at higher temperatures the reverse is true. It is suggested that hybrid vigour, fluctuating selection intensities, and migration may all play a part in maintaining the observed distribution of the various forms.

This publication has 0 references indexed in Scilit: