418 BOTANICAL GAZETTE [NOVEMBER 
as the writer has had occasion to examine have in every case proved 
to be exceptionally long as compared with the proportions of the 
aerial parts. The roots run down for long distances into the fis- 
sures in the flows, and often pursue the most devious courses. 
The following plants exhibit this condition: Acacia koa, A. Far- 
nensiana, Alphitonia excelsa, Artemisia australis, Cassia Gaudi- 
chaudii, Cheirodendron Gaudichaudii, Coprosma montana, Dodonaea 
eriocarpa, Erythrina monosperma, Geranium cuneatum, Gossypium — 
tomentosum, Lipochaeta subcordata, Metrosideros polymorpha, 
Myoporum sandwicensis, Osteomeles anthyllidifolia, Perrottetia sand- 
wicensis, Psidium guayava, Reynoldsia sandwicensis, Rumex gigan- 
teus, Senecio vulgaris, Sida fallax, Sophora chrysophylla, Styphelia 
tametameiae, Waltheria americana, Wikstroemia spp., Xylosma 
Hillebrandia. 
Sclerophyllous formations 
A considerable proportion of the lava vegetation may be 
classified as sclerophyllous. The leaves of these species are thick 
coriaceous, usually with glistening, highly reflective upper surfaces. 
Antidesma, Chrysophyllum, Coprosma, Maba, Metrosdieros, Notho- 
cestrum, Osmanthus, Pelea, Pisonia, Pittosporum, Pterotropia, 
Sideroxylon, Styphelia, Wikstroemia, and Xylosma are genera con- 
taining typical coriaceous-leaved species. It should be noted that 
Hawaii does nt exhibit the extreme sclerophyllous condition, but 
rather a semi-sclerophylly. For example, many species with 
sclerophyllous foliage do not show noticeable dwarfing; indeed, 
they may be trees of considerable stature. In the Hawaiian 
Islands the sclerophyllous formations occur at the higher levels 
(5000-9000 ft.), and altitude seems to be a dominant factor in their 
origin and zonation. 
AGE OF LAVA FLOW VEGETATION.—The vegetation of the lava 
flows is largely comprised of woody, long lived species. These 
acquire the aspect and habit of senility at a relatively early stage 
in their life cycles. The unfavorable conditions of the environ- 
‘ment stamp themselves upon the physiognomy of the individual 
‘plants and of the formations as a whole. The woody species give 
every evidence of great age and slow growth. Shrubs 4-6 ft. 
