Dodds and Simmonds (1946) described the meiosis in 
this species, and they also found that their material had 
72 chromosomes in the root tips. They observed an aver- 
age of 25-30 bivalents and 10-12 univalents and about 
two multivalents at diakinesis. They also observed non- 
congressed univalents and bivalents at metaphase I, lag- 
gards at anaphase I, and micronuclei at quartet stage. 
Finally, they suggested that 7'r7psacum lawum is an am- 
phidiploid, and correlated the sterility of their plants 
with meiotic irregularity. 
Cutler (1947) stated that T'ripsacum laxum, as well as 
T. pilosum and T’ latifolium, was usually sterile, and it 
did not produce any viable seeds. 
As the result of a meiotic study on the Brazilian spe- 
cies Tripsacum australe, Graner and Addison (1944) con- 
cluded that it was a diploid. No knobs were observed on 
any of the chromosomes, although knobs frequently 
occur on the chromosomes in other species of the genus. 
The present study consists of observations on certain 
meiotic features in two tropical Tripsacums from Colom- 
bia, probably referable to T’ripsacum lawum Nash and 
T. australe Cutler and Anderson, respectively. It is 
hoped that it will provide some cytological bases for in- 
terpreting the phylogenetic relationships of the species 
concerned. 
MarERIALS AND METHODS 
The clone of T'ripsacum laxwum was first collected near 
Buenaventura, Colombia, where it had been introduced 
from Puerto Rico. It is cultivated under the name cava 
antigua. The plants are unusually large and vigorous, 
even for 7". dawum, with numerous stout tillers, but rarely 
set any viable seeds. The staminate spikelets are paired, 
with one sessile and one pedicellate spikelet. Presumably 
of hybrid origin, it seemed worthy of cytological inves- 
tigation. 
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