Euphorbiaceae. 
often more than 10 inches. The trunk is vested in a pinkish, rather thin bark 
which is smooth when young, but often forms thick knobs which are deeply 
wrinkled in very old trees. It has a tremendous flow of latex, which does not 
coagulate on the tree, but becomes yellow, especially in old trees. 
The species occurs in the guleches back of Makawao, Maui, and also on the 
slopes of Mauna Kea, Hawaii, near the crater Nau, on the boundary of the 
Parker and Horner ranches. The writer met with it also on the Island of Lanai 
in the dry gulches of Mahana. 
The new variety, however, occurs only on the slopes of Hualalai between Hue- 
hue and Puuwaawaa, Hawaii, at an elevation of 3000 feet, on the rough aa lava 
fields and also in the more humid forest of Waihou. The area with which this 
tree is practically covered amounts to about 5000 acres. During a recent visit in 
North Kona, engaged in botanizing in this most interesting locality, the writer 
was struck by the tremendous flow of latex and the large amount which could 
be procured from a single tree. Thinking it worth while to take some latex 
samples for examination, the writer sent a large bottleful to the U. S. Agricul- 
tural Experiment Station in Honolulu for analysis. 
This Station has since published the results of the analysis in the form of a 
Press Bulletin No. 37, entitled ‘‘ Huphorbia lorifolia, a Possible Source of Rubber 
and Chicle,’? by Wm. McGeorge, Assistant Chemist, and W. A. Anderson, Su- 
perintendent Rubber Substation 
Euphorbia Rockii Forbes. 
Koko. 
(Plate 101.) 
eatery ROCKII Forbes Occas. Pap. Bernice P. Bishop Mus. Vol. IV. 3. (1909) 38, 
Leaves a. a raped se ee se: uneven-sided with a clasping base, ponds 
Sessile, 8 to 12 em long, 2.5 to 3 ¢ e; flowers in open axillary cymes 3 to 3.5 em lo 
pee ca Becearage minutely Fa arg or glabrous on the outside, pubescent on the ealde 
lobe 8S ovate, min , glan nds waunveney 6 oblong, not appendiculate; style branches short, 
nearly tn free; males large 18 to 24 mm. glabrous, pink or dark crimson, on nodding 
This tree, which was discovered by the writer in August, 1908, when in full 
fruit is exceedingly handsome. It reaches a height of about 15 to 20 feet, with 
a trunk of about eight inches in diameter. The bark is smooth and whitish. 
Like all Euphorbiae, it exudes a sticky, milky sap when bruised. The branches 
are flat and spreading, giving the trees a broad, flat crown. The flowers are 
small and inconspicuous and are borne on dichotomous cymes. The three-cor- 
nered capsules are bright pink or deep scarlet when mature, of an inch or more 
in length clothing the whole crown in scarlet, which is beautifully contrasted 
with the dark-green, glossy, sessile foliage. 
The Euphorbia Rockii is peculiar to the Island of Oahu, and is only found 
on the windward side, in the mountains of Punaluu above Kaliuwaa valley, at 
an elevation of 2000 feet or more. On the summit ridge it grows to a shrub. 
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