Spermatogenesis in certain Hepaticae

Studies of Spermatogenesis in the Hepaticae

An ultrastructural study of late-stage androgonial cells of Blasia pusilla, a thallose liverwort, showed the nearly spherical nuclei often lying close or appressed to the cell walls. In some cells the two membranes comprising the nuclear envelope separated, the inner membrane continuing intact as a limiting boundary of the nucleus and the membrane on the outer, cytoplasmic side recurving away f...

Origins of Neotropical Leafy Hepaticae

The neotropical hepatic flora, predominantly constituted by members of the Jungermanniales and Metzgeriales, includes a disproportionate number of genera which are endemic (over 38) and a number which evidently originated here but have shown slight and in a geological sense, modern dispersal by solitary species. Endemism is confined almost to the Jungermanniales; it is to a large degree of a un...

Flavonoids from Some Frullania Species (Hepaticae)*

Z. Naturforsch. 50c, 345-352 (1995); received January 27/February 20, 1995 Liverworts, Frullania, Flavone Aglycones, Acylated Flavone Glycosides, Chemotaxonomy From Frullania teneriffae 5 known flavone aglycones and 6 flavone glycosides were iso­ lated, among them the new 6-OH-luteolin-6-0-ß-D-glucoside-7-0-ß-D-glueoside-6'"-(3-hydroxy-3-methylglutaroylester). F. cesatiana contains 2 flavone-di...

Chromosomal Abnormality in Men with Impaired Spermatogenesis

AN ULTRASTRUCTURAL STUDY OF PLANT SPERMATOGENESIS Spermatogenesis in Nitella

Spermatogenesis in the charophyte Nitella has been followed in antheridia prepared for light and electron microscopy. The antheridial filament cells contain paired centrioles which are similar in structure and behavior to the centrioles of animal cells. In the early spermatid, the centrioles undergo an initial elongation at their distal ends and become joined by a spindle-shaped fibrous connect...