112 MISSOURI BOTANICAL GARDEN. 
tion are not thought to be the primary factors leading to 
the development of the habit of leaf reflexion. 
The primary cause which leads to the development of 
this habit is probably to be found in the relations between 
light and growth, and the necessity for some such habit to 
free the plant from rubbish which becomes lodged in the 
erect crown of rigid leaves. 
Yucca brevifolia, illustrating the Clistoyuccas, is unique 
in having a light spongy fruit which falls when mature 
and is blown about as a rolling fruit, gradually breaking up 
and dropping the seeds. 
The capsular Yuccas, like filamentosa and glauca, are de- 
veloped for wind dissemination. They have very thin light 
seeds which are gradually sifted out of the capsules and 
blown to some distance by the wind. 
The wind disseminated Yuccas grow in open places where 
the wind can have free action upon them. 
The rotting off at the base and falling of the old fruit 
stems of jilamentosa serves finally to throw out all seeds 
which remain in the capsules. 
Eustis, Florida. January 12th, 1895. 
EXPLANATION OF PLATES ILLUSTRATING THE DISSEMINATION 
OF YUCCA. 
Plate 45.— Yucca aloifolia, with lateral branch developing from near 
the base of the peduncle. The leaves of the phytomeroid which bore 
the inflorescence have begun to reflex.—Drawn by Mrs. Webber, from 
a photograph ofa plant at Bartow, Florida, January 24, 1894. 
Plate 46. — Y. aloifolia, with lateral branches starting at the base of 
the old peduncles, and the leaves of the upper phytomeroid starting to 
reflex.—From a photograph of plants on Anastatia Island, Fla., Jan. 23, 
1895. 
Plate 47.— Fig. 1. Ripe fruit of Y. aloifolia — Fig. 2. Cross section of 
aloifolia fruit. — Fig. 3. Basal end of old peduncle of Y. aloifolia cut off 
at a by Prodoxus decipiens; bb, scars resulting from oviposition of Pro- 
doxus female; cc, perforations made by the chrysalis of Prodoxus in 
issuing; d, portion of the epidermis cut away by the burrowing of Pro- 
doxus; ee, tunnels in the tissue made by Prodoxus larve.— Fig 4. Y. 
aloifolia seed, and cross section of seed showing ruminated endosperm.— 
Fig. 5. Capsule of Y. jfilamentosa. — Fig. 6. Y. silamentosa seed, and 
cross section. — All nat. size, drawn from nature by Mrs. Webber. 
