A systematic survey of the Articulatae series of the genus Selaginella and monographic treatment of the S. sulcata group (Sensu Str.) / Paul Somers Jr.

Tese (Ph.D.) - University of Tennesse, Knoxville, 1978

A systematic survey of the Articulatae Series of the Genus Selaginella was made. The study concentrated mainly on the bistelar taxa and resulted in monographic treatment of those recognized by the author as the S. sulcata group (sensu str.). The morphological studies, involving leaf clearings, spore measurements and SEM observations, aided in distinguishing useful from abiguous characteristics. During the study it was discovered that the Articulatae are characterized by a unique type of microsporangium. Chemical studies reulted in the identification of (1) a red pigment, rhodoxanthin, found in sters of many of the taxa and (2) orientin and luteoolin based compounds, the first report of either of these types in the genus. The flavonoid studies helped to distinguish two taxa in the S. diffusa complex, characterized by the presence of multicellular cilia on their leaf margins, from taxa in the allied S. horizontalis complex, which have only unicellular cilia or serrations on their leaf margins. Selaginella diffusa and S. stellata populations consistently had both orientin and luteolin type compounds, whereas populations from the S. horizontalis complex lacked luteolin type compounds or possessed only trace amounts of them. As a result of this investigation, major nomenclatural changes were made involving typification of S. stellata Spring and S. suavis Spring. Reputed type material of S. glaziovi Fée, S. schizobasis Baker, S. fragilis A. Br., and S. arenaria Baker were found to be composed of mixed collections; these were reinterpreted. Taxonomic changes consisted of: (1) two new combinations: S. horizontalis var. eurynota (A. Br.) Somers and S. horizontalis var. microtus (A. Br.) Somers and (2) many taxa being placed into synonymy: S. suavis (Spring) Spring, S. glaziovi Fée, S. caudorhiza Bak. and S. biauriculata Hieron. = S. sulcata (Desv. in Poiret) Spring; S. schizobasis Bak. = S. sertata Spring; S. galeottii Spring = S. stellata Spring; S. mnioides (Sieber) Spring, S. macrophylla (A. Br.) Hieron. and S. eggersii Sod. = S. diffusa (Presl) Spring, and S. intacta Bak., S. lindigii A. Br. and S. expansa Sod. = S. lingulata Spring.