1900] LIFE HISTORY OF QUERCUS 417 
8. The first division of the oospore is transverse, and the sus- 
pensor undergoes but one subsequent division, which is vertical. 
_ ENGLISH HIGH AND MANUAL TRAINING SCHOOL, 
icago. 
EXPLANATION OF PLATES XXVIII-XXIX. 
The figures are reduced from drawings traced by means of a Bausch ana 
Lomb camera. Nos. I, 9, 12, 13 were made with Reichert objective no. 7; 
the others with a Spencer ora Bausch and Lomb + oil immersion with ocular 
combination magnifying 1200 and 1300 diameters. 
Fig. 1. Longitudinal section through two stamens showing winter stage. 
Fig. 2. Section of an anther, same date as above, showing cells of uniform 
character, more highly magnified. 
Fig. 3. Section of anther of date April 22; shows differentiation into wall, 
tapetal, and sporogenous regions; the inner wall cells showing evidence of 
collapse. 
Fic. 4. The formation of tetrads from the pollen mother cell. 
Fic. 5. The mature spore with generative and tube nuclei. 
Fig. 6. Two tapetal cells showing the binucleate and multinucleolate con- 
dition preceding final disintegration. 
1G. 7. Transverse section of the ovary showing loculi and placental folds 
(4h); March 7. 
1G. 8. A section of the placental fold more highly magnified ; March 7. 
Fig. 9. Longitudinal section of a carpel; marks the beginning of the 
ovule and the development of hairs from the inner surface of the carpel; 
pril 21. 
Fic. 10. Transverse section of the placental fold; April 21. 
Fig. 11. Section of the ovule showing the first indication of the integu- 
ments (ee) ; ay 5. 
IG. 12. Outline of the transverse section of the ovary showing the three 
loculi each containing two ovules; one loculus shows the hairs with which 
the cavity becomes almost completely filled; the ovules, nearly enclosed by 
the integuments, have assumed a position almost at right angles to the p ea 
of the section. 
Fig, 13. Outline of the section of the nucellus with its inte 
Same as fiz. 12. ' 
Fics. 14-20, Longitudinal section of the nucellus showing the extent and 
Position of the archesporial cells; dates ranging from May 13 to May 22; hg. 
20 is a section almost at right angles to the long axis of the nucellus. 
Fig. 21. A row of five cells showing a tendency to develop into mega- 
Spores; the middle cell has taken the lead and the cells immediately above 
and below are breaking down. 
= 
guments ; date 
