36 BOTANICAL GAZETTE [JANUARY 
2. The greatest variations occur when the megaspores and the 
oldest microspores are blasted, and when strong plants develop a few 
sporocarps out of season. 
3. Enlargement does not appear among the microspores when less 
than half the spores abort, and the surviving spores are larger the 
greater the amount of abortion. 
4. The mother cells may be checked in their development till the 
tapetal nuclei completely invest them. A perinium will then form 
around the mother cell wall, which invests the four young spores. In 
such cases the sporangium invariably contains sixteen large forms 
each containing four nuclei. At other times, when growth is less 
checked, the spores are more or less completely free and show great 
variation in size and shape. 
5. The contest for supremacy among the young megaspores of 
each sporangium is very evident, many of them assuming consider- 
able proportions, but one, centrally located, invariably secures the 
ascendency. Sometimes the contest is very close between two or 
more members of the same tetrad. Very often the surviving member 
will carry attached to its papilla the aborted members even to germi- 
nation. 
6. The enlarged microspores vary in size, the largest being 8-16 
times the size of the ordinary ones; the position of the nucleus chan- 
ging from a central (usual) to an apical one, as in the megaspores. As 
vacuolation is more extensive, the shape of the nucleus also varies from 
the usual spherical form to the oval, and finally in the largest to the 
meniscus shape, as in the megaspore. 
7. In extreme cases of abortion in the microsporangia only one 
spore survives, which is about 16 times as large as the normal micro- 
spore. The aborted tetrads remain as in the megasporangium, but 
are much larger and better developed, thus showing a sharper and 
more prolonged contest for supremacy. 
8. In plants kept from sporocarp-formation until September 10, 
many microsporangia developed secondary megaspores, so call 
because they are formed after the first or primary ones. Such mega- 
spores are intermediate in size and are also more nearly the spherical 
shape of the microspores. 
g. A few cases were noted in which the megaspores did not 
