EXPLANATION OF THE ILLUSTRATION 
Prare XXII. Diagram of the 18 chromosomes in 
Tripsacum australe. The lengths, arm ratios, spin- 
dle fiber attachment regions (broken line), large 
chromomeres (small dots), and knobs (large dots) 
of the chromosomes are determined by actual meas- 
urements and observations at pachytene in the 
microsporocytes. Chromosome 16 has a nucleolar 
organizer (circle) in the long arm. The chromo- 
somes are divided into two groups, A and B: group 
A has the nine long chromosomes, group B, the 
nine short chromosomes. 
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