404 BOTANICAL GAZETTE [NOVEMBER 
between these cracks is commonly every 2 or 3 ft. in all directions. 
The flow is thus broken up into irregular polyhedral blocks, which 
tend to separate under weathering and gravity. In old flows these 
cracks may become several inches wide and are commonly utilized 
by plants as growing places. The fresh pa-hoe-hoe is shining jet 
Fic. 14.—Close view of ropy or festooned pa-hoe-hoe on floor of Kilauea; note 
concave upper faces of festoons in which seeds and spores are caught and plant life 
first established. 
black and in arid situations retains this appearance for an indefinite 
period. Under humid conditions, however, it weathers rapidly 
and becomes brown or reddish, due to the oxidation of its high 
iron content. On the pa-hoe-hoe fields the plant life occurs chiefly 
in the furrows or wrinkles of the ropy areas and in the numerous 
fissures that are abundant in the surface of the smoother areas. 
