1915] 
In O. pratincola 
A well-grown plant, is 1.5 m. high, 
and loosely branched. 
The basal branches are frequently 
simple. 
The flowering time lasts about six 
weeks, 
The lax terminal spike often be- 
comes 5-6 dm. long (see fig. 1). 
The lateral branches below the 
terminal spike are few in number 
and become 4-5 dm. long. 
The lowest bracts of the upper 
lateral spikes are ovate, and grade 
upward to lanceolate. ‘ 
The calyx segments are so sparsely 
pilose as to appear practically gla- 
brous. 
The hairs of the calyx segments are 
about 1 mm. long, thick-walled, acute, 
with multicellular tuberculate bases. 
BARTLETT—MUTATION IN OENOTHERA 87 
In O. numismatica 
A well-grown plant, is about 1 m. 
high, and densely branched. 
The basal branches bear tertiary 
branches and resemble the ‘main — 
stem. 
The flowering time lasts only about 
two weeks. 
The dense terminal spike is about 
2 dm. long in fruit (see fig. 2). 
The lateral branches below the 
terminal spike are numerous and are 
seldom over 2 dm. long. 
The lowest bracts of the upper 
lateral spikes are nearly orbicular 
ade upward through oblong 
to lanceolate (see fig. 2). 
The calyx segments are closely 
and finely pubescent. __ 
The hairs of the calyx segments are 
less than o.5 mm. long, and belong 
to two types: (1) an acute thick- 
walled type without tuberculate bases, 
and (2) a thin-walled, round-ended, 
clavate or cylindrical type. 
Technical diagnoses of these two species, together with a discus- 
sion of their possible relationships, have been published elsewhere.” 
O. pratincola appears to be a frequent plant in the North Central 
States. O. numismatica, on the contrary, is known only from 
Lexington and may well be a local species, possibly derived by 
mutation from O. pratincola. Its close resemblance in certain 
characters to one of the mutations of O. pratincola is pointed out 
elsewhere in this paper. 
The mutations of ‘Lexington C” 
Seeds from four of the parent plants of O. pratincola which had 
been selected at Lexington were planted early in the spring of 1913. 
 Bartterr, H. H., Twelve elementary species of Onagra. Cybele Columbiana 
1237-56. 1914. : 
