191 1-] TRELEASE— THE DESERT GROUP XOLIXE.E. 409 



tors are to be sought probably among the Hymenoptera and Dip- 

 tera, as has been suggested to me for Dasylirion by Sr. Patoni, of 

 Durango, 



Normally fertilized, the ovules develop into 3-sided or 3-grooved 

 seeds with micropyle by the side of the hilum, a slender often 

 scarcely discernible raphe, and thin and smooth or somewhat thick- 

 ened and wrinkled envelopes composed of thin-walled cells and 

 representing essentially the seed-coats though often with a terminal 

 umbo or apiculus representing the base of the nucellar tissue. The 

 bulk of the seed consists of rather firm endosperm through which 

 the finger-like embryo passes upward from near the micropyle 

 toward the morphological base of the nucellus. The endosperm 

 consists of moderate-sized polygonal cells with glistening white 

 rather thick pitted walls and coarsely granular contents destitute of 

 starch. The walls of these cells are of the " reserve-cellulose " type, 

 but they are colored blue by neither iodine nor chlor-iodide of 

 zinc, though they swell so greatly in the latter reagent that in a 

 thick section the contents, in which large and abundant oil drops 

 separate out, promptly extrude, sausage-like, from any chance 

 break (pi. 10). Went and Blaauw-'- have reported partial embryo 

 formation in some ovules and much more complete endosperm de- 

 velopment in others, in a pistillate Dasylirion. — apparently without 

 concurrence of male nuclei. Usually only one of the six ovules pro- 

 duced by a normal pistil matures in the i -celled fruit of Dasylirion 

 and Bcaucarnca or the 3-celled ovary of Calibanus; but with the 

 3-celled fruit in NoUna, though a single seed is the rule, two or three 

 are not infrequently seen, — usually only one to a cell, though ex- 

 ceptionally both ovules of a carpel develop. 



The ripened fruit is dry-walled : subglobose with three low ribs 

 in Calibanus, triangular with strongly developed dorsal wings on 

 the carpels in Dasylirion and Bcaucarnca, and deeply 3-lobed be- 

 tween the wingless carpels in Nolina. In the first three genera it 

 does not dehisce, but in Nolina, though the delicate walls are often 

 irregularly torn — sometimes even before maturity of the rather 

 firmly attached seed, or the fruit may remain long unopened — loculi- 

 cidal dehiscence is more or less prevalent (pi. 11, 12). 



If observations on dissemination have been published, they have 



