5. An inbred strain gave in F2 approximately 65% of luteus seedlings. This aberrant ratio was caused by the linkage of a gene for small pollen with the normal allelomorph of the luteus gene. Small pollen (sp) has 2% crossing over with luteus. A variable percentage of the eggs with the small pollen gene abort giving in different F2 populations a range from 55 to 90% of luteus seedlings. Small pollen germinates as rapidly as normal pollen but never, or rarely, succeeds in fertilization. Cytological examinations at pachytene showed no visible deficiency. The gene for small pollen is being tested with sp1.