Collins and Kempton: Patrogenesis 
TRIPSACUM DACTYLOIDES 
Plant perennial. 
Staminate and pistillate flowers in the same 
inflorescence. 
Terminal inflorescence with 
branches. 
Branches of terminal inflorescence erect. 
Branches of terminal inflorescence without 
pulvini. 
No secondary branches in terminal inflor- 
escence. 
from 1 )to 3S 
Staminate spikelets in pairs both sessile. 
Staminate spikelets in alveolae. 
Pistillate inflorescence naked. 
Outer glume of pistillate inflorescence com- 
pletely exposed. 
Stigmas about 2 cm. long. 
Stigmas divided to the base. 
Inflorescence basipetal. 
Fruit trapezoidal. 
Rachis not constricted between the seeds. 
No branches in axils of prophylla. 
Leaf blades about 50 times as long as wide. 
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DURANGO EUCHLAENA 
Plants annual. 
Staminate and pistillate flowers in different 
inflorescences. 
Terminal inflorescence with from 8 to 20 
branches. 
Branches of terminal inflorescence drooping. 
Branches of terminal inflorescence with 
pulvini. 
Secondary branches in terminal inflores- 
cence equalling or more numerous than the 
primary. 
Staminate spikelets in pairs one sessile, the 
other pedicelled. 
Staminate spikelets not in alveolae. 
Pistillate inflorescence enclosed in bracts. 
Outer glume of pistillate inflorescence par- 
tially enclosed by the rachis. 
Stigmas from 10 to 15 cm. long. 
Stigmas divided for about 3 mm. 
Inflorescence acropetal. 
Fruit triangular. 
Rachis constricted between the seeds. 
Branches in the axils of prophylla. 
Leaf blades about 10 times as long as wide. 
the surface of the ground our faith was 
still so small that the plant was dug up 
and the seed examined to make sure 
we were not rearing a “cuckoo.” As 
the sprout was found to be growing 
from an unmistakable Tripsacum seed, 
it appeared certain that the plant was 
either a hybrid or a parthenogenetically 
developed Tripsacum. The second al- 
ternative was soon dismissed, for Euch- 
laena characters appeared with the first 
leaves, and the further stages of 
development were those of a nearly 
normal Euchlaena plant. Most careful 
scrutiny failed to disclose any characters 
that could be referred to Tripsacum, the 
female parent. The plant was not 
exactly like others that had been grown 
previously, but even under the most 
favorable greenhouse conditions, Euch- 
laena shows many deviations from the 
normal behavior. The deviations in 
this were not extreme or unusual, 
indeed the plant was more nearly like 
normal Durango Euchlaena than any 
Euchlaena we have ever been able to 
grow under greenhouse conditions. 
Two points regarding this cross should 
be kept in mind: (1) the plant was 
known to have grown from a seed borne 
on a Tripsacum plant; (2) the plant 
resembled the male and not the female 
parent. These two facts taken together 
eliminate all questions of foreign pollen 
or faulty technique. 
The plant was grown to maturity in 
the greenhouse, was carefully guarded 
and _ self-pollinated and produced a 
quantity of seed. Unfortunately no 
Tripsacum pollen was available at the 
time the first generation plant was in 
flower, October, 1913, but plants of a 
Florida Euchlaena were just beginning 
to shed pollen and this was applied to a 
number of the pistillate inflorescences. 
Two very late varieties of tropical corn 
were also in flower and pollen from them 
was similarly used. All the pollinations 
were successful, seed setting as readily 
with the corn and Euchlaena pollen 
as with the plant’s own pollen. 
THE SECOND GENERATION 
A few seeds representing each class 
of pollinations were planted in the 
greenhouse in December, 1913. From 
this planting there were secured seven 
plants, with the following parentage: 
Three plants from self-pollinated seed 
of the first generation cross; one plant 
from the first generation cross pollinated 
with Florida Euchlaena; two plants of 
the first generation cross pollinated with 
a Liberian variety of maize; one plant 
of the first generation cross pollinated 
with a variety of maize from Bolivia. 
The last plant was soon eliminated as 
the result of a peculiar abnormality. 
The sheath of the first leaf instead of 
being open on one side and enclosing 
