206 MISSOURI BOTANICAL GARDEN. 



The typical Yucca glauca, as represented in Colorado 

 and Kansas, spreads below ground by a series of rather 

 slender but very strong axes, and in its more highly 

 developed form has a more or less developed mostly pros- 

 trate stoutish trunk above ground. So far as I know, 

 whether caulescent or acaulescent, a given axis usually 

 blooms repeatedly. 



Y. GLAUCA, var. STRICTA, (Sims.). (Y. angustifolia, 

 var. mollis, Engelm.) (PI. 22). In its broader flaccid 

 leaves, occasionally an inch wide, this forms an approach 

 from glauca to the Eastern filamentosa, but its range, 

 Arkansas, Louisiana and Texas, brings it strictly within 

 the region of the former and its immediate allies. Unlike 

 the more representative glauca, however, a given crown 

 seems more likely to fruit but once, though the subterran- 

 ean parts are similar in both. Its delicate greenish-white 

 flowers, most commonly in a simple raceme, possess the 

 general characters of those of the type, and are slightly 

 fragrant. The styles, though somewhat variable in color, 

 are commonly bright green as in the type, so that they 

 contrast with the ovary, which is colored similarly to the 

 perianth. The stylar canal is open and in evident com- 

 munication with, the cells of the ovary, and at times con- 

 tains a plentiful secretion. No nectar was observed at 

 Dallas, Texas, where I had an opportunity of examining 

 the flowers in several localities, but the septal glands are 

 large and with large conducting grooves, as is generally the 

 case in the filamentosa group. 



Many years ago Boll * made a number of observations 

 about Dallas on the Yuccas, some of which were doubtless 

 of this variety. While he did not at first discriminate be- 

 tween Pronuba and the related Prodoxus decipiens, which 

 Professor Riley has well called the Bogus Yucca Moth, 

 and especially the still more deceiving Prodoxus intermedium, 



* Boll, Stettin. Entomolog. Zeitung, 1876, 401, quoted by Riley i 

 Trans. St. Louis Academy, iii. 571. 



