MISSOURI BOTANICAL GARDEN BULLETIN 79 
these plants ever live to be a hundred years old; in fact, very 
few live for more than half that time. The agaves are 
peculiar in that they flower but once during their entire 
existence. From infancy to maturity the plant continues to 
put out new and larger leaves in which quantities of water 
and reserve food materials are stored. At maturity a large 
flower stalk, in appearance not unlike a fresh sprout of 
asparagus, is produced from the center of the rosette of 
leaves. All the reserve material that has been stored in the 
leaves contributes to the formation of this stalk, its flowers, 
and its fruits, and by the time the seeds are ripe the leaves 
are withered and the plant is dead. 
Among the genera of smaller plants with leaves not unlike 
those of agave should be mentioned Dyckia, one of the South | 
American genera of bromeliads, Aloé, and Haworthia—be- 
longing to the lily family and a native of Africa. Another 
enus with fleshy-leaved species is Mesembryanthemum, of 
outh Africa. Some members of this group have thick 
tongue-shaped leaves, and others are so peculiarly constructed 
that they have been called the “tiger’s jaw.’ In others, 
ain, the leaves grow together in such a way as to give the 
whole plant the appearance of a small puff ball. Echeveria, 
of Mexico, and Sempervivum, of the Mediterranean region, 
commonly known as “hen and chickens,” have short, thick 
leaves arranged in a close rosette. Dudleya and Stylo- 
phyllum, of the coast of California and Mexico, produce 
a of cylindrical or sub-cylindrical, very succulent 
eaves. 
Obviously, all the forms of succulent desert plants to be 
seen in the Garden collection cannot be considered here, 
and what has been said is intended merely to give some idea 
of this unique and interesting group of plants, and to indi- 
cate some of the adjustments which have enabled these plants 
to maintain themselves successfully in the desert regions. 
GERANIUMS 
Few garden plants have been longer or more aie in 
use than the several varieties of geraniums. The parent 
species of Pelargonium from which most of the present-day 
varieties of geraniums have been derived, were introduced 
into England two centuries ago from South Africa, and a 
century ago many species were in cultivation in Europe and 
the work of hybridization had begun. Since that time the 
work of breeding has continued more or less actively and has 
resulted in the production of a very great number of horti- 
cultural varieties. Most of these are of the zonal or bedding 
