(1) Three morphological types were identified in seeds which set by intraspecific hybridization of tulips, i.e. :
A. morphological complete seeds (germinant)
B. embryo deficient seeds (non-germinant)
C. abortive seeds（non-germinant)
(2) In 1953～1954, authors made the following classification according to the crossability on reciprocal crosses of tulips varieties.
Group I. While the capsule sets in reciprocal crosses.
In these capsules,
a. morphological complete seeds set only.
b. morphological complete seeds set on the one and none on the other cross.
c. morphological imcomplete seeds set only.
Group II. When the capsule sets on the one and none on the other cross in reciprocal crosses.
In these capsules,
a. morphological complete seeds set only.
b. morphological imcomplete seeds set only.
Group III. Before the capsule sets.
(3) The same combination gave highly differences in the percentage of sets in each of 2 years.
(4) There were impotences as maternal parents, in such varieties as Princess Helen, Zwanenburg, White Pision and in all varieties of double tulip strain.