236 Campbell, — Contributio?is to 
The Macrospore and Female Prothallium. 
The macrospores are formed in the sporangia of the outer 
leaves, and are very much larger than the microspores, from 
which they differ in form, being of the tetrahedral type. They 
are nearly globular in form, and, like most tetrahedral spores, 
the three ridges where the spore is in contact with the others 
of the tetrad, are very conspicuous, and may be seen with a 
hand-lens. If the fresh spore is crushed in water, its contents 
appear milky, and microscopic examination reveals oil-drops 
and some starch-granules mingled with roundish bodies of 
albuminous nature. The latter absorb water more or less, 
and look almost like free cells. While, as we have already 
stated, it is quite impossible to section the fresh spores, by 
hardening with alcohol or chromic acid, it is not difficult to 
imbed them, and then sections may be easily made; and 
when stained with some aniline colour (gentian-violet or 
safranine), the structure is readily made out. 
The wall of the spore is composed of several layers of 
which the outer one (Epispore) is thick and glassy in texture, 
and in our species provided with short recurved spinules (Fig. 
40, sp). The interior is filled with coarsely granular proto- 
plasm that often appears spongy, owing probably to the 
dissolving out of the oil in the process of imbedding (Fig. 1). 
Scattered through the spore are round starch-grains (Fig. 1, s), 
having a central hilum. Besides the starch-grains are nu- 
merous somewhat irregular bodies (Fig. 1, Al) that stain 
strongly with gentian-violet or safranine, and seem to be 
albuminous reserve-materials. The nucleus is large and 
readily seen. It lies in the basal part of the spore — that is 
the part opposite the point of contact with the other spores 
of the tetrad. The nucleus is broadly elliptical in form, and 
a small space about it is usually nearly free from the larger 
starch-grains and albuminous granules. Not infrequently, 
between the nucleus and the wall of the spore, a close layer 
of small starch-granules was observed that was very con- 
spicuous (Fig. 1, /). The nucleus (Figs. 2, 3) has a delicate, 
