| Abstract: | Summary We take here into consideration the embryologic study of Tulipa Oculus-solis St. Am v. praecox, a species which became naturalized in the northern Sardinia, and we notice that contemporaneously to the development of the embryo-sac according to Euphorbia dulcis type (85% frequency), which was already described by Bambacioni (1931), we may have also the development according to Adoxa type (15% frequency). We show here the hypothesis that the possibility of developping the embryo-sac according to unlike types (but genically kindred ones) is not depending upon an early or a delayed vacuolisation, caused by either external or internal casual factors, but on the contrary is the manifestation of a peculiar tendency which is connected with the particular genetic caracteristic of the Species. |
