332 PROCEEDINGS OF THE ACADEMY OF [1887. 



reaching its full length. The pollen is remarkably large, there be- 

 ing only about 25 grains in each cell. The stigma seems receptive 

 co-incident with the maturity of the pollen. There is nothing to 

 suggest any special arrangements for cross-fertilization. The flow- 

 ers are odorless. Moths visit the flowers freely. The moth remained 

 a long time feasting on a single flower, generally from two to three 

 minutes. It used the mass of filaments with the style for a platform 

 on which to work for the nectar at the base of the style. Its mo- 

 tions would tend to shake the pollen out into the flower's own stigma 

 and aid in self-fertilization. Large numbers of the flowers on my 

 plants are barren. Many have not one, some have but one, and 

 rarely are there two seeds in a single involucre. 



Besides the three flowers that are produced in each involucral 

 cup, a branch occasionally proceeds from the same axis. The flow- 

 ers are usually regarded as apetalous, but a close examination of an 

 opening flower is strongly suggestive of an amalgation of the corrol- 

 line and calycine whorls in one perianth. As the flower is opening 

 the bud presents what a superficial examination would regard as 

 a five-cleft calyx, with green-lance-linear and hairy segments, and 

 it would be a surprise to an original observer to find a mono-pet- 

 alous corolla, wholly in one piece with what appeared to be a dis- 

 tinct calyx. At the apex of one of the segments, and Avhich by the 

 way are alternate with what should be petals, there are two small 

 pin-like, white glands ; at the apex of another one gland ; and at the 

 apex of a third a small and imperfect one. This indicates that the 

 elementary pai*ts forming the floral whorl did not coil rapidly on its 

 spiral course ; as also does the successive development of the sta- 

 mens ; we may reasonably look for some irregular flowers among its 



congeners. 



Iri'itability in the Stamens of Echinocaetus. It has been long 

 known that the stamens of many Opuntias are irritable or sensitive 

 when fully expanded under a hot sun. I have placed on record 

 that this character extends to other allied genera. This summer I 

 noted that the stamens of Echinocaetus Ottonis, were particularly 

 irritable. 



Diurnal opening of the floivers of Magnolia glauca. My brother 

 Joseph called ray attention to the fact, that cut flowers of Magnolia 

 glauca, in water in our office, opened at 4 P. M. I found this to be the 

 case also with plants growing in the open air, no matter whether the 

 sun was shiniiig, or the sky cloudy. They open at 4 P. M. but close 



