FERTILIZATION OF THE CRIMSON THREAD-FLOWER 



( Poinciana Gillesii ). 



By Bessie L. Putnam. 



I HAVE been much interested in the fertilization of Poinciana Gil- 

 lesii, and thus far have not satisfied myself as to the manner in 

 which it is accomplished. 



In the large flower clusters there are seldom more than four 

 or five blossoms open at once, these opening successively from below 

 and the flowering stem lengthening as they expand. So far as I have 

 observed, the greater part of the flowers open between mid-day and 

 sunset, though some appear earlier in the day. The slender and 

 beautifully colored stamens, fully thrice the length of the corolla, 

 are coiled and packed into the bud with exquisite daintiness (Fig. i ). 



FIG. I. 



FIG. 2. 



When the flower opens the stamens and pistils assume the posi- 

 tion shown in Fig. 2, the stigma apparently studiously avoiding any 

 possible contact with the anthers. Later, probably the following day, 

 the essential organs assume the relative positions shown in Fig. 3 b, 

 the stigma no longer receptive, and most of the pollen scattered. 

 Twenty-four hours later most of the stamens have fallen (Fig. 3^). 



Evidently fertilization is but imperfectly performed in this north- 

 ern clime, for in no instance did more than three or four of the large 



