318 
GENETICS: J. A. HARRIS 
The axis may be either round and slender throughout or considerably 
broadened, or even divided. Of the plants about 30% show division 
of the epicotyl into two or more branches; about 50% are recorded as 
producing shoots from the axils of the cotyledons. 
The race is characterized most specifically by the doubHng of the 
number of cotyledons and primordial leaves. The most frequent num- 
ber of cotyledons is four, instead of two as is normal in the species. 
Leaves. 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
Cotyledons 
2 
3 
^4 
[5 
6 
7 
3 
7 
1 
2 
20 
51 
1 
11 
69 
114 
7 
3 
95 
187 
12 
1 
8 
74 
140 
14 
2 
5 
36 
97 
20 
2 
28 
55 
4 
2 
1 
1 
18 
38 
5 
3 
1 
4 
24 
3 
3 
13 
4 
2 
7 
1 
1 
1 
1 
33 
352 
734 
73 
9 
1 
11 
74 
201 
298 
238 
158 
92 
65 
32 
20 
10 
2 
1 
1202 
The average number is somewhat less than four. The modal number 
of primordial leaves is also four, but the average number is considerably 
higher than this number. 
The range of variation in number of cotyledons and of primordial 
leaves is very wide. The table, which gives the frequency of the various 
combinations of cotyledon and leaf number in several hundred seedlings 
studied in 1915, shows that plants with from 2 to 7 cotyledons and with 
from 1 to 14 primordial leaves were observed. These distributions 
show a variation of about 20% of the mean for number of cotyledons 
and of about twice that amount for number of leaves. The most fre- 
quent combination is that of four cotyledons and four primordial leaves, 
but the range of combinations is very wide, and correlation in conse- 
quence very low. 
Variation in the new race is not limited to number of organs, but is 
conspicuous in the structure of cotyledons and leaves as well as of the 
axis. The most of the cotyledons are large and typical in form but 
occasionally those which are small and scale-Hke are observed. They 
may be inserted in a regular whorl or widely scattered along the axis. 
The leaves vary greatly in insertion, size, form and texture. Foliar 
ascidia are abundant. 
History of origin and morphological characteristics are discussed and 
fully analyzed statistically in a paper appearing in an anniversary vol- 
ume of the Memoirs of the New York Botanical Garden. 
