January 31, 1908] 



SCIENCE 



193 



correlation between parent and offspring in 

 characters subject to normal, or " fluctuating," 

 variation, if such variations are not in fact 

 transmitted. 



E. P. BiGELOW 



Massachusetts Institute op Technology, 

 Boston, Mass. 



aggregate mutation of gossypium 

 Dr. O. F. Cook, in his ofiicial work for the 

 TJ. S. Department of Agriculture, has observed 

 several instances of abrupt change en masse of 

 the distinguishing characters of varieties of 

 cotton, full results of which he is preparing 

 to publish. Some of those transmutations 

 have occurred in connection with geographical 

 transference, and some have not. Central 

 American varieties on being brought to the 

 United States have shown entirely distinct 

 characters of habit and growth in all the 

 plants from and after their first planting. In 

 case of the well-knovm and long-cultivated 

 upland cotton of the United States, he found 

 all the individual plants of a whole planting 

 to have become thus abruptly changed. The 

 change involved the whole field crop of a 

 planting, and the new crop differed equally 

 from both the parent stock and the plantings 

 of the same stock in other fields in the same 

 season. 



Dr. Cook properly regards these transmuta- 

 tions as identical in character with those 

 which I have observed in the tomato and which 

 in several publications I have designated as 

 aggregate mutation. See especially Popular 

 Science Monthly, Vol. LXVII., No. 2, June, 

 1905. 



Charles A. White 



SPECIAL ARTICLES 



THE chromosomes OF OENOTHERA 



On account of the general interest which at- 

 taches to this subject, it may be well to pre- 

 sent some further facts, and also to review 

 briefly our knowledge of the subject as de- 

 veloped up to the present time. The work is 

 being continued upon a large amount of ma- 

 terial collected during the summer from a cul- 

 ture which consisted of 1,Y00 pedigreed indi- 



viduals, partly from pure races, and partly 

 from guarded crosses. The collections made 

 from each individual were kept separate from 

 all others for examination. My work on the 

 subject was begun on plants grown at Woods 

 Hole, Mass., from seeds of DeVries, in 1905. 



In December, 1906,' some of this work was 

 reported upon. 0. lata from a cross was 

 found to have 14 chromosomes as sporophyte 

 number, but quite unexpectedly one of the 

 other plants from what was believed to be pure 

 seeds of 0. lata X 0. Lamar chiana were found 

 to contain 20 chromosomes. This result was 

 published in a paper^ on the abortive pollen 

 development in 0. lata, but it was discovered 

 by the writer' a little later that 0. Lamar ch- 

 iana itself had 14 chromosomes. This result 

 was afterwards confirmed by Miss Lutz,' and 

 Geerts in a short paper" published the same re- 

 sult. After my first announcement of results 

 Miss Lutz germinated seeds of several forms 

 and examined the root-tips of the seedlings, 

 finding* about 14 chromosomes in 0. Lamarch- 

 iana, as already stated, but 28 or 29 in 0. 

 gigas. 



I have since reported' 14 chromosomes in 

 the Lamarckiana plants from 0. lata X 0. 

 Lamarckiana as well as in the 0. lata from 

 this cross, also in 0. rubrinervis and in 0. 

 nanella; together with various peculiarities 

 of the reduction mitoses in the pollen mother 

 cells of these forms. One of these interesting 

 features is that sometimes in the heterotypic 

 mitosis one chromosome passes to the wrong 

 pole of the spindle, thus probably introducing 



' American Association for the Advancement of 

 Science, New York meeting. 



^ " Pollen Development in Hybrids of (Enothera 

 lata X 0. LamarckioMa, and its Relation to Mu- 

 tation," Bot. Gazette, 43: 81-115, 1907. 



" " Hybridization and Germ Cells of CEnothera 

 Mutants," Bot. Gazette, 44: 1-21, 1907. 



* " A Preliminary Note on the Chromosomes of 

 CEnothera Lamarckiana and one of its Mutants, 

 0. gigas," Science, N. S., 26: 151-152, August 2, 

 1907. 



° " tjber die Zahl der Chromosomen von (Enoth- 

 era Lamarckiana," Ber. deut. Bot. Gesells., 25: 

 191-195, 1907. 



' International Zoological Congress, Boston, 

 August 22, 1907. 



