American Journal of Botany, Vol. 35, No. 6 (Jun., 1948), pp. 343-349 (7 pages) The female gametophytes of Hesperocallis undulata Gray and Leucocrinum montanum Nutt. follow the normal type of ...

1. The cyathium of both species studied begins as a papilla which arises between two bracts. The order of appearance of the parts of the cyathium is as follows: staminate flowers, involucre, ovules, ...

SEVEN ‘Golden Delicious’ apple clones propagated from buds irradiated at 5,000 r. in a cobalt-60 source were selected for high, intermediate, and low pollen abortion. Pollen abortion was 4.9 per cent ...

MEMBERS of the family Loranthaceæ are characterized by many abnormal features in the development and organisation of the embryo sac, endosperm and embryo 1,2,3. In June 1949, one of us (P. M.) ...

A gradient (red) in the concentration of auxin, a plant hormone, determines that only one of the eight undifferentiated nuclei in a plant's embryo sac will become an egg. (In this image, a large ...

A gradient (red) in the concentration of the plant hormone auxin determines that only one of the eight nuclei in a plant's embryo sac will become an egg. (The blue island in the image is a cell ...

Microscopy image of a PGA at day 8 showing the early tissues supporting the embryo, including the amniotic sac and the yolk sac-like structures, surrounded by (extra-embryonic) mesoderm tissue.

The first few weeks after sperm meets egg still hold many mysteries. Among them: what causes the process to fail, leading to many cases of infertility. But scientists haven't had a good way to explore ...