THE SPERMATOPHYTES 479 
whorls or spirals set around a shortened axis, the floral axis or 
receptacle, torus or thalamus, or, as in the more modified 
Angiosperms, the floral axis may even become hollow. 
3. In Gymnosperms the microsporophylls or stamens are 
usually sessile, whereas in Angiosperms the microsporophylls 
are nearly always stalked. Rarely do we find sessile anthers 
among Angiosperms, an instance of this being seen in Mistletoe 
(Viscum) where the anthers are set on the staminal leaf. 
4. In Gymnosperms there is a traceable prothallus or gameto- 
phyte plant that later becomes the so-called “‘endosperm’’ of 
the gymnosperm, whereas in Angiosperms no recognizable 
prothallus has been proven to exist. 
5. The stored food tissue in Gymnosperm seeds is prothallial 
tissue loaded with starch, etc., whereas in Angiosperm seeds the 
stored food tissue fendldeperat} is a — formation after 
fertilization. 
6. Gymnosperms bear naked ovules and seeds while Angio- 
sperms bear covered ones. 
7. In Gymnosperms there are distinct recognizable arche- 
gonia formed on or imbedded in the prothallus, whereas in 
Angiosperms there are no distinct archegonia, only an isolated 
egg or eggs. 
8. In Gymnosperms there are not infrequently found several 
embryos from one fertilized egg. ‘This condition is called poly- 
embryony. Polyembryony is unknown in Angiosperms, only a 
false polyembryony being noticed. 
9. In Gymnosperms the secondary xylem (wood) tissue of 
roots, stems and leaves consists either of punctated or scalariform 
cells, whereas in Angiosperms the secondary wood tissue may be 
varied in structural aspect. 
CLASSES OF ANGIOSPERMS 
The Angiosperms are subdivided into two classes, the Mono- 
cotyledonez or Monocotyledons, and the Dicotyledoneze or 
Dicotyledons. 
The Monocotyledons include such plants as the cat-tails, 
grasses, sedges, palms, lilies, daffodils, irises, bananas, gingers 
and orchids. The Dicotyledons are represented by a vast 
