SYSTEMATIC SIGNIFICANCE OF SEED MORPHOLOGY IN SAGINA (CARYOPHYLLACEAE) UNDER SCANNING ELECTRON-MICROSCOPY

The seed morphology of 15 species of Sagina from North America, Europe, and eastern Asia was studied, utilizing the scanning electron microscope, to determine the significance of seed coat features as taxonomic characters. There is variation in particular surface features within some members of the genus. However, superficial ridges and tubercules exhibit patterns very helpful in determining relationships among some species. Two basic seed types occur in the genus and are diagnostic at the sectional level. The saginoid seed, characteristic of section Sagina, is obliquely triangular in outline, is grooved along the two dorsal ridges, and has slightly concave lateral surfaces. The crassuloid seed, characteristic of section Maxima, is obliquely reniform in outline, lacks dorsal grooves, and has shallowly convex lateral surfaces. © 1979, The New York Botanical Garden. All rights reserved.