BOTANICAL MUSEUM LEAFLETS 
HARVARD UNIVERSITY 
CamsripGE, Massacnusetts, JUNE 30, 1960 VoL. 19, No. 4 
CYTOLOGICAL OBSERVATIONS ON TWO 
TROPICAL FORMS OF TRIPSACUM 
BY 
Y. C. Tine! 
SINCE the successful crosses between T'ripsacum dacty- 
loides Li. and maize were reported by Mangelsdorf and 
Reeves in 1931, the genus T’ripsacum has become more 
interesting to both taxonomists and geneticists. Despite 
this, only a limited number of species in this genus have 
been cytologically investigated (Longley, 1924 and 19387; 
Reeves and Mangelsdorf, 1935 ; Mangelsdorf and Reeves, 
1939; Anderson, 1944; Graner and Addison, 1944; 
Dodds and Simmonds, 1946; Hernandez and Randolph, 
1950; Prywer, 1954; Maguire, 1957 and 1960). Most of 
the previous studies consisted of the determination of 
chromosome numbers and an interpretation of the ho- 
mology between the chromosomes of Tvipsacum and 
those of Zea. In addition, some discussed the phyloge- 
netic relationship among different species in the genus 
(Mangelsdorf and Reeves, Anderson, and Graner and 
Addison). 
The chromosome number of T'ripsacum lawum Nash 
has been reported as about 2n=70 by Longley (1924) 
from a study of meiotic divisions. However, based on the 
mitotic divisions in the root tips, Mangelsdorf and Reeves 
(1939) stated that the chromosome number was 72. 
‘Research Fellow in the Bussey Institution, Harvard University. 
[ 97 ] 
