188 MISSOURI BOTANICAL GARDEN. 



by no means as effective in preventing close fertilization as 

 in brevijolia and Wkipplei, which are described below. 

 The bright golden yellow pollen is readily seen on any part 

 of the flower in contact with which it may have come, and 

 particularly, on the nearly white ovary and the pure white 

 style. 



The latter is not usually as long as in the flower figured 

 in the lust Report and already referred to. It has a very 

 open stigmatic tube which passes into the upper ends of the 

 ovarian cells, as may be seen in some cases even by looking 

 down the wide channel with the aid of a hand lens, for there 

 is little stigmatic secretion. In this species it is also very 

 easy to convince oneself that the three pollen-conducting 

 grooves, similar to those figured by Webber for gJauca* 

 but also seen in Agave and other plants with this type 

 of pistil, are formed by the uppermost part of the infolded 

 edges of the carpels, which further down coalesce to form 

 the true septa, and constitute the placenhe. As in other 

 Yuccas, each septum of the ovary contains a nectar gland ;f 

 but the glands of baccata are not so large and open as in 

 the filamentosa group of species, in this respect agree- 

 ing with those of the other fleshy-fruited Yuccas that I 

 have examined. Notwithstanding this, they appear to be 

 rather more active than in the former group (herein 

 agreeing with Guatemalenxis among the baccate species, 

 gloriosa among the spongy-fruited species, and the Hespero- 

 yuccas), their secretion sometimes appearing in small 

 quantity at the base of the pistil, where their large ducts dis- 

 charge. Several of the flowers examined at San Diego in 

 the morning were very wet on the outside, a condition which 

 has-been observed on other species; J but though it is 



* American Naturalist, 1892, 303, 309, pi. 13, f. 38. 



f Trelease: Bulletin of the Torrey Bot. Club, 1886, 135, and Third Gar- 

 den Report, pi. 63; Riley, I. c. 109, Proc. Biol. Soc. Washington, vii. 91, 

 and Insect Life, iv. 364 to 306. 



X Y. filamentosa,— Meehan, Proc. Phila. Acad. 1888, 276, and Trelease 

 Third Garden Report, 123; Y. gloriosa,— Meehan, Proc. Phila. Acad. 1880,' 

 355, 1883, 191; and Hespero yucca, mentioned below. 



