382 The Ohio Naturalist. [Vol. VI, No. 1, 



The development of the embryo from this stage on was not 

 traced very closely but the divisions must occur rather rapidly 

 for on May 23rd the embryo had reached about the 12-celled 

 stage (Fig. 15). On May 29th a large spherical embryo was 

 present (Fig. Hi). The suspensor had lengthened considerably 

 and sections showed a dovible row of cells (Fig. 1(3). At this time 

 the antipodals were degenerating (Fig. 17). They lie in a broad 

 depression at the base of the sac which is greatly enlarged and 

 tilled with endosperm. The behavior of the antipodals recalls the 

 condition of these cells in certain Ranunculaceae. On June (ith 

 the ovules had matured and were falling to the ground. The 

 integument is very hard and it was found necessary to remove 

 it before imbedding in paraffin. At this time the embryo was 

 much larger and the two cotelydons were well developed (Fig. 

 18). The suspensor was still present but showed signs of 

 degeneration. 



SUMMARY. 



The flowers of Sanguinaria begin to develo]) verv earlv in 

 the summer previous to the year in which they blossom. 



The development of the microsporocvtes and microspores is 

 much more rapid than that of the megaspores for the micro- 

 spores are formed before the winter season begins. 



The ovule passes the winter in the megasporocvte stage and 

 during March its development is very rapid while the microspore 

 does not renew activity until the last of March and early April. 



Three parietal cells are formed and later these divide forming 

 a parietal tissue of considerab'e size. 



The division of the megasporocyte frequently results in 

 rather typical tetrads. 



The generative nticleus does not appear to divide in the 

 pollen grain. 



The long resting ])eriod of the oosphere is especialh' 

 interesting. 



BIBLIOGR.VPHV. 



1. VHsguE, J. 



Nouvelle recherches sur le development du sac embryon- 

 naire des Phanerogames Angiospermes. Ann. Sci. Nat. Rot. 

 VI, 8:261 3<)(), Pis. 12-21. 1879. 



2. vStrasburc.kr, E. ■' ■ § 



Neue Untersuchungen uber den Befruchtungsvorgang 

 bci (Icn Phanerogamen. Jena. 1884. 



3. Shaw, Chari.ks H. 



Notes on sexual generation and the develo])ment of the 

 seed coats in certain of the Papaveraceae. Bull. Tor. Bot. 

 Club 31:429 43:}, PI. 15. 1904. 



