1. Seedlings have been obtained from reciprocal crosses involving both triploid and pentaploid forms of Tulipa. The other parents of these crosses were diploids and tetraploids. 2. The chromosome numbers of these progeny have been determined. The majority of them are aneuploids. 3. The triploid, either as a male or female parent, tends to contribute less than one-half the somatic number of chromosomes. This is probably explained by the irregularities in the meiotic divisions of this type. 4. Although the number of progeny from the pentaploid is small, a similar condition exists.