Verbatim text: Horner, H. T. Jr. and H. J. Arnott. 1963. Sporangial arrangement in North American species of Selaginella. Bot. Gaz. 124: 371--383.
Author: Horner, H.T., Arnott, H.J.
Year: 1963
Title: Sporangial arrangement in North American species of Selaginella
Journal: Bot. Gaz
Volume: 124
Pages: 371–383
PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/336222