An embryological study of Isotoma longiflora Presl

Abstract

1. The anther shows a wall with only three layers; the tapetum becomes binucleate; pollen grains are tri-nucleate at shedding stage. 2. The ovary has innumerable anatropous ovules attached on a massive central placenta. Megasporogenesis proceeds normally and the embryo sac is formed according to the normal type. 3. The embryo is formed according to he Capsella-type. 4. Endosperm isab initio cellular, and is formed according to thePhyteuma-type described by Rosen. 5. A slight departure from the above type is met with in a large propertion of ovules, and since this is also quite a distinctive one, it may be regarded as a type, theIsotoma-type. 6. A reference to the systematic position of the genusIsotoma is made in the paper.