40 
mists that hang around the hills every morning in the winter and 
spring-time. In this way these growths obtain moisture enough 
to enable them to reach maturity. Besides this the Atacaman 
plants have acquired several peculiarities which admirably adapt 
them to their conditions of life. One of these lies in the power 
of the seeds to live for many years in the dry sand without ger- 
minating. They have been known to retain their vitality for-ten 
years and then to sprout at the touch of rain. 
I suspected from appearances that a special weather protection 
existed in many or all of these seeds, and Dr. Gregory of Barnard 
College, who has, at my request, kindly examined microscopic sec- » 
tions of a number of species, confirms my suspicions so far as these 
particular species are concerned. The seeds in every case proved 
to have unusually thick walls and a copious supply of albumen 
around the embryo. In one instance (Piztoa) she reports that the 
“‘seed coats are heavy, the outer one having peculiar shaped cells 
which turn to mucilage on coming into contact with water.”’ An- 
other (a 7ristagma) has “copious albumen and the outer walls 
are thickened and turned in color toa dark brown, making an ex- 
tremely hard coat.” Calandrinia seeds presented a coating 
‘‘somewhat heavy, but with a.peculiar readiness to break on con- 
tact with water.” Cvristaria has an integument of several layers 
which together make a thick wall, and the interior albuminous. | 
Viola shows ir the seed coat a contrivance similar to that of Pzx- 
toa, -with more or less of albumen in the interior. 
While seeds are thus fortified against a protracted drought, 
tubers and bulbs are equally well equipped by the large amount 
of water or milk which they store up. I found many of the bulbs 
that I collected so full of juice that I could squeeze it out ina 
stream by hand. : 
Another peculiarity of the herbaceous flora, evidently ac- 
quired, is the early age at which the plants begin to flower and 
fructify. As if aware that they have only an ephemeral life and 
that what they have to do must be done quickly, they are scarcely 
above ground before they put forth blossoms. Many species 
may be seen in flower when hardly an inch in height, and which — 
go on flowering until they reach the stature of two or three feet— 
if they can survive so long. . I was continually deceived by this _ 
