1908] GATES—REDUCTION IN OENOTHERA 31 
5. It is suggested that there is probably a direct relation between 
the events of reduction in a given genus and its variation, as well as its 
hybridization phenomena. 
I desire to express my thanks to Professors JOHN M. COULTER 
and CHARLES R. Barnes for valuable suggestions and adequate 
facilities in connect’on with this work. 
THE UNIVERSITY OF CHICAGO 
LITERATURE CITED 
I. ALLEN, C. E., Nuclear division in the pollen mother cells of Lilium canadense. 
Annals of Botany 19:189-258. pls. 6-9. 1905. 
———., Das Verhalten der Kernsubstanzen wahrend der Synapsis in den 
Pollenmutterzellen von Lilium canadense. Jahrb. Wiss. Bot. 42:72-82. 
pl. 2. 1905. 
BErcus, JULEs, La formation des chromosomes hétérotypiques dans mirs la 
sporogénése végétale. I. Depuis le spirtme jusqu’au chromosomes mfrs, 
dans la microsporogénése d’Allium fistulosum et Lilium lancifolium (speci- 
osum). La Cellule 21:173-189. pl. 1. 1904 
. Depuis la sporogonie jusqu’au spirbme définitif, dans la micro- 
sporogénése de |’ Allium fistulosum. Idem 21:383-397- pl. 1. 1904. 
: , III. La microsporogénése de Convallaria maialis. Idem 22:43-50. 
- I. 1905. 
6. 
» 
= 
* 
st 
- La microsporogénése de Drosera a Narthecium 
ossifragum, et Helleborus foetidus. Idem 22:141-160. pls. 2. 1905. 
Carpirr, Ira D., A study of synapsis and reduction. Bal Torr. Bot. 
Club 33: 271-306, pls. 12-15. 1906. 
- Farmer, J. B., and Moore, J. E. S., New investigations into the reduction 
phenomena of socials and plants. Pree Roy. Soc. 72: 104-108. igs. 6. 1903- 
: , On the maiotic phase (reduction divisions) in animals and plants. 
Quart. ‘ies Micr. Sci. 48:489-557. pls. 34-41. 1905. 
70. Farwer, J. B., and SHovE, Dororxy, On the structure and development of 
the somatic aiid oo chromosomes of Tradescantia virginica. Idem 
48:559-569. pls. 42, 43. 
- GatEs, R. R., Pollen caer in hybrids of Oenothera lata X O. 
Lamarckiana, aad its relation to mutation. Bot. GAZETTE 43:81-115. 
907. 
oy 
oo 
Lal 
Lal 
bls. 2-4 
12. ——__ , Bivladtieation and germ cells of Oenothera mutants. Idem 44:1-21. 
Jigs. 3. 1907. 
a ~~; International Zool. Congress, Boston, Aug., 1907. 
Mee ~———, The chromosomes of Oenothera. Science N. S. 2'7:193-195- 1908. 
S- a Further studies on the chromosomes of Oenothera. Idem 27:335. 
