SUPPLEMENT 



but they usually bloom late, and only on the more northern hills and 

 mountains. The golden-star lily is Bloomeria aurea, Kell.; its tall, 

 showy umbels deck many a dry hillside after the greater part of the 

 spring vegetation, including its own leaves, has withered. The 

 flowers, which seem so openly hospitable, really exclude all but bees 

 and butterflies from their honey by means of peculiar appendages at 

 the base of the stamens. The soap-root will be taken up in Chapter 

 XV, also some of the genus Iviltum that bloom in summer. 



The Yucca of the illustration is Y. Whipplei, Torr , which, with its 

 variety graminifolia, is common throughout the southern foot-hills. 

 After some years of preparation, the rootstock with its clusters of 

 bayonet-like leaves, sends up a flower stem which, in a few weeks, 

 attains a height of from ten to fifteen feet and bears literally 

 thousands of flowers, forming one of the most beautiful flower panicles 

 in nature. The tree Yucca, or " Yucca palm," of the Mohave Desert 

 is Y. arborescens, Torr., a remarkable plant in its details, as well as in 

 general appearance. From its base countless roots, slender as whip 

 cords, radiate in every direction, extending long distances but lying 

 near the surface. Its trunk and branches are for a long time clothed 

 with savage, reflexed leaves, but when these finally fall, the stem is 

 seen to have acquired bark of considerable thickness, and a section of it 

 shows concentric rings characteristic of exogenous rather than endoge- 

 nous stems. The growth of this Yucca stem and of another phenomenal 

 endogen, the dragon-tree of W. Africa, which has been known to 

 attain seventy feet in height and sixteen feet in diameter, has 

 received much attention, but the subject is beyond the scope of this 

 work. Y. Mohavensis, Sargent, with fleshy, purplish fruits, has a 

 wide range in California and in the South West generally, and is 

 extremely variable in form. 



The pollination of the Yuccas has" long been a subject of close 

 observation and study by both botanists and entomologists. The 

 story as told in the Reader applies to any of the species. The three 

 common California species have been individually investigated ; they 

 are pollinated by three different, but nearly related species of moths ; 

 their methods of procedure vary to some extent, but the leading facts 

 are the same in all cases. The moths that pollinate Y. Whipplei and 

 its variety may be frequently seen at work before dark. Most species 

 of Yucca mature their stigmas before the anthers, and there is always 

 a stigmatic cavity (very slender indeed in Whipplei); the moths 

 always seek newly opened flowers for depositing their eggs, so the 

 pollen they bring is nearly always from other flowers. The moth 

 does not seem to require food during her brief existence as a moth 



102 



