286 NOTES ON THE GENUS YUCCA. 
than of others, are extremely variable in shape, and this seems to be caused principally by the 
irregular development of the seeds. When these fail near the middle, the capsule becomes con- 
stricted (very often in the true Y. filamentosa) ; when near the top, it usually is beaked (forms of 
Y. rupicola); so that detinite diagnostic characters cannot be derived from these apparently so well- 
marked differences in the shape of the capsule. In the species just named, and in the Y..baccata, 
the beak of the fruit may also be the result of the development of an elongated style. 
The substance and the surface of the capsules would also seem to afford good distinctions, for 
we find the capsule in some, thin, membranaceous, and smooth ; in others, thick, ligneous, cross- 
wrinkled, with thick carinal and also lateral ridges, aud sometimes warty ; but I have observed such 
differences in forms of the same species, and especially in Y. jilamentosa, which seems to 
be one of the most variable species, perhaps, only because we know more of it than of the [32] 
others. 
SEEDS. 
The seeds of the Yuccas are compressed, of a triangular-obovate or obliquely ovate, or some- 
times even orbicular form, the straighter inner margin with the indistinct rhaphe corresponding with 
the secondary dissepiment, and the angle at its base containing the hilum. They vary in size 
from 6-12 or 13 mm. in diameter, and 0.6-3.5 mm. in thickness. The thin, black, more or less 
opaque testa exhibits under a strong power elevated cells or tubercles, each with or without one or 
several pits or impressions; in some forms these cells appear larger and irregularly rugose, but I 
have, thus far, not been able to discover constant specific characters even in the seed surface. 
The seeds are of three different forms, corresponding with the three kinds of fruit. The baccate 
Yuccas have the thickest seeds (2.0—-3.5 mm.), of an uneven rugose or undulating surface, with a 
very narrow two-edged rim, and a deeply lobed or ruminated albumen, as already indicated by 
Torrey, in Bot. Mex. Bound., in the instance of Y. baccata; I have been able to examine only the 
seeds of this species, Y. aloifolia and Y. Treeuliana. Clistoyucea has a thinner seed (2 mm.), with a 
little more distinct rim, and with an even albumen. All the capsular Yuccas have the thinnest 
seeds (0.6-1.2 mm.), with a very distinct, narrower or wider, thin and brittle margin, and with an 
even albumen. 
@ semi-transparent, hard, almost corneous, farinaceous and oily albumen (ruminated in 
Sarcoyucea, plain in all the others), contains the straight or mostly more or less curved axile embryo, 
which extends diagonally from the hilum, to which the short. caulicle points, almost to the epposite 
margin, thus attaining the full length of the albumen. Only very rarely and in imperfect seeds I 
have seen a shorter embryo, such as Gaertner figured and Kunth described, as being less than one- 
half or only one-fourth as long as the diameter of the albumen. The slit in the base of the cotyle- 
don, under which - a is concealed, shows the cotyledon to be about four or five times as 
long as the ca 
MONSTROSITIES. 
I have seen very few abnormal developments of Yuccas, and these only in the flowers. 
Tetramerous flowers with an eight-parted perigon, eight stamens and a four-carpellary ovary [33] 
and fruit, more or less regularly developed, are not quite rare in cultivated as well-as wild 
plants. In overgrown garden specimens of Y. angustifolia, I have seen flowers irregularly doubled, 
the number of perigonial lobes increased, some of them yet bearing the traces of anthers, or filaments 
bearing perfect anthers, with petaloid excrescences or wings, also filaments adnate to the ovary, and 
some of them even tipped with the green stigma of the species. In a cultivated form of Y. jila- 
mentosa, the floral axis was elongated, the perigonial segments separated and increased in number, 
the exterior somewhat foliachons; and bearing regular or irregular axillary flowers. 
