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AMERICAN JOURNAL OF BOTANY 
Table i. History of Oenothera franciscana B. 
[Vol. 9, 
Culture 
13.21 
14.21 
15.21 
16.21 
17.21 
19.21 
20.21 
21.21 
Source of Culture 
(Culture and Plant) 
Bartlett 106-126 
13.21a, c 
14.21a 
15.21 
i6.2ia 
17.21, III-i 
19.21, III-2 
20.21, 5 
Description of Culture 
52 plants, uniform 
18 plants, ' ' 
16 plants, ' ' 
9 plants, " 
12 plants, " 
No culture 
15 plants, uniform 
25 plants, " 
1,352 mature plants 
21 remaining as rosettes 
1,373 uniform and typical 
1,520 uniform and typical 
It will be seen from this table that during the eight years in which this 
strain has been carried along, not a single mutation or aberrant form has 
been discovered. There is very little pollen sterility, and the seed tests 
made by Dr. Davis (table 2) show that the percentage of seed sterility 
is also very small. 
Table 2. Seed Fertility in Oenothera franciscana B. 
Year 
i 
Culture 
Procedure 
Result of Test 
Percentage of 
Germination 
1915 
15.21 
Contents of two capsules, seeds 
germinated in earth 
442 seedlings 
280 seed-like 
structures 
722 
61% 
1919 
19.21 
Contents of one capsule, soaked 
24 hours. Subjected to alter- 
nate exhaust and pressure (50 
lbs.) twice in 24 hours 
398 seedlings 
43 seed-like 
structures 
441 
90.2% 
1921 .... 
21.21 
Contents of three capsules, 
soaked 24 hours. Subjected to 
alternate exhaust and pressure 
(30 lbs.) 7 times in 24 hours 
1,425 seedlings 
209 seed-like 
structures 
1,634 
87.3% 
All the indications so far, then, point to Oe. grandiflora and Ge. fran- 
ciscana, and especially to the latter species, as likely to prove genetically 
pure. In view of this fact, it becomes a matter of extreme interest to 
investigate these plants cytologically and to compare them from this 
standpoint also with the members of the Lamarckiana group. The matura- 
tion divisions in the pollen mother cells of Oe. grandiflora have been studied 
by Davis (1909). He made the interesting discovery that in this species 
the seeming incompatibility between homologous chromosomes, which is 
so characteristic of the plants of the Lamarckiana series, and which seems 
in their case to point strongly to a hybrid nature, is lacking. The homol- 
