

[Vol. 2 



114 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



and the parallel venation of some leaves is a special 

 modification derived from it. 



C. DICTA HAVING REFERENCE TO THE FLOWERS OF FJX)WERING 



PLANTS 



15. The polymerous flower structure precedes, and the oligo- 



merous structure follows from it, and this is accom- 

 panied by a progressive sterilization of sporophylls. 



16. Petaly is the normal perianth structure, and apetaly is the 



result of perianth reduction (aphanisis). 



17. The apochlamydeous perianth is earlier and the gamo- 



chlamydeous perianth is derived from it by a symphysis 

 of the members of perianth whorls. 



18. Actinomorphy is an earlier structure than zygomorphy, 



and the latter results from a change from a similar to 

 a dissimilar growth of the members of the perianth 



whorls. 



19. Hypogyny is the more primitive structure, and from it 



epigyny was derived later. 



20. Apocarpy is the primitive structure, and from it syncarpy 



was derived later. 



21. Polycarpy is the earlier condition, and oligocarpy was de- 



rived from it later. 



22. The endospermous seed is primitive and lower, while the 



seed without endosperm is derived and higher. 



23. Consequently, the seed with a small embryo (in endo- 



sperm) is more primitive than the seed with a large 

 embryo (in scanty or no endosperm). 



24. In earlier (primitive) flowers there are many stamens 



(polystemonous) while in later flowers there are fewer 

 stamens (oligostemonous). 



25. The stamens of primitive flowers are separate (apostem- 



onous), while those of derived flowers are often united 

 (synstemonous). 



26. The condition of powdery poll on is more primitive than 



that with coherent or massed pollen. 



27. Flowers with both stamens and carpels (monoclinous) pre- 



cede those in which these occur on separate flowers 



(diclinous). 



