330 CALIFORNIA ACADEMY OF SCIENCES. [PROC. 3D Ser. 



to depend on citations and fragmentary reviews for my 

 knowledge of it. It is an exhaustive work, describing the 

 complete development of the floral and reproductive organs 

 of the cultivated barley as well as its embryology. Koer- 

 nicke, on the other hand, studied the development of the 

 stamen and embryo-sac of the wheat with especial reference 

 to cytological phenomena. Two studies which were made 

 before the introduction of the modern methods of imbedding 

 and sectioning, viz. by Fischer (1880), and Norner (1881), 

 were consulted in the preparation of this paper. Fischer's 

 study deals with the development of the embryo-sac of 

 various grasses, while that of Norner treats of the embry- 

 ology alone. All of the contributions mentioned above 

 refer to grasses belonging to the branch of the family known 

 as the Poaceas, the members of which, besides being closely 

 related, have very similar habits and habitat. It is to be 

 greatly desired that future studies of the Gramineas may 

 include representative grasses of various habits and habitat of 

 both branches of the family. In this way an adequate knowl- 

 edge of the inter-relationships of the grasses, as well as 

 their relationships to other Monocotyledons may be obtained, 

 and also a better idea of the origin of plant structures. In 

 addition to the papers already named there is a great mass 

 of work on the comparative morphology of the different 

 parts of the mature flower and of the mature embryo. Be- 

 ginning with Malpighi {Omnia ope?'a, 1687), and Gartner 

 one hundred years later, the series extends with little inter- 

 ruption to the present. For a review of these works the 

 reader is referred to the studies by Bruns (1892), and to the 

 recent one by Kennedy (1899). 



Because the flower of the wild oat is the type grass flower, 

 (it is described and figured in any good text-book of botany), 

 it was selected for this morphological study. The wild oat 

 is supposed to be the ancestor of the cultivated species, or 

 at least the nearest relative of that ancestor, and is one of 

 our commonest grasses. It was presumably introduced into 

 California at an early date from Southern Europe, and has 

 now a wide range throughout the state. 



