124 A YEAR OF COSTA RICAN NATURAL HISTORY 



here shows an Intermediate stage between the bare cinders 

 produced by an eruption and the fully clothed summit of a 

 long-extinct volcano. Such vegetable islands are due to 

 the accidental lodging of some Individual of the pioneer 

 species by whose roots the cinders are held together so that 

 other and different seeds can sprout and obtain a foothold 

 In the shelter of the first. Standing In the cinders and 

 among the growing plants are a great many small dead 

 trees, all about the same size and all bleached quite white. 

 These dead trees are not oaks; they were seen in January, 

 1847, by Oersted who mentioned them as Comarostylis ruhes- 

 cens (now termed Arctostaphylis Icsdifolia), one of the 

 heaths. One of the most common and, because of its num- 

 bers, conspicuous plants of these cinder gardens was a pretty 

 little geranium {Geranium mexicanum). Its flowers are 

 one-half to three-quarters of an Inch across, from a pure 

 white to a deep pink In color, daintily veined in purple. It 

 starred the slopes wherever grasses had obtained foothold 

 and then It reminded us strongly of our own "spring beau- 

 ties." It grew through the huckleberries and myrtles and 

 opened Its delicate blossoms among the glossy leaves of the 

 stronger plants. Another common plant, growing several 

 feet high, was Spiraa argentea, with stiff, thick racemes of 

 small. Inconspicuous but very fragrant white flowers. A 

 curious little fern (Botrychium obliquum) was growing among 

 the geraniums. Dr. H. Christ, of Basle, wrote of our speci- 

 men of this fern, "that it does not differ in any respect from 

 those from the north of the United States and that this 

 species plays In Costa Rica the role of a glacial relict ("reli- 

 quat glaclaire"). 



At the very summit nothing grew — probably the wind 

 was too strong. It took us a long time to reach this point 

 as the trailing In the cinders is slow and tiresome, but at last 

 we turned down Into the crater Itself. Looking north from 



