THE GENUS PLANTAGO IN HAWAII 
Joseph F. Rock 
The Hawaiian Islands possess two endemic species of Plantago, of 
which one, PI. princeps, is a branching shrub. The only other known 
species which is a branching shrub is Plantago fernandezia, a native of the 
island of Juan Fernandez. As far as we know PL fernandezia is not a 
variable species, while PL princeps is exceedingly variable and is represented 
in Hawaii by eight varieties. Curiously eijough the typical form has not 
been collected since the days of Hillebrand. 
Plantago princeps is primarily a plant of the lower and drier region, 
occurring only on the leeward side of Oahu, Kauai, and Molokai. It is 
true some forms grow near waterfalls (var. longihracteata) and exposed 
to the force of the water, and others grow on drier slopes in stands (var. 
elata). Three varieties of PL princeps grow usually near water courses 
(var. d-enticulata, var. longihracteata, and perhaps var. hirtella). The stem- 
less form (var. acaulis) occurs in the rain forest on clay banks, as does var. 
Queleniana. Plantago princeps var. elata reaches a height of six feet, while 
var. denticulata with a height of four feet is the next tallest ; all forms occur 
from these heights to short, simple stems and stemless plants. 
Wawra, who studied the different forms of this and the other species 
more thoroughly than any previous botanist, lays especial stress, and that 
rightly, on the venation, which is parallel and free in Plantago pachyphylla, 
while in Plantago princeps the lateral veins converge and join the median 
nerve. The pyxidium dehisces at the base in PL princeps; in PL pachy- 
phylla it dehisces at the middle. The seed in PL princeps is viscous, linear, 
and black, while in PL pachyphylla the seeds are supposedly oval, light 
brown, and not viscous. None of the characters, including the branching 
and stemless habit of the two species, hold good, nor can they be relied 
upon as specific characters. This brings us to the conclusion that both 
species are closely related and even hybridized, which is proven by the 
numerous forms exhibited by both species. Yet if one should take the 
very small forms of PL pachyphylla (var. pusilla) from the summit swamp of 
Kauai, Mt. Waialeale, and compare them with the var. mauiensis, one could 
describe them as distinct species, although there are gradations to be found 
which to a large extent link these two varieties together. 
The main link between PL princeps and PL pachyphylla is furnished 
by a new variety (var. anomala) of the former species. That variety has 
the capsules and leaf venation of PL pachyphylla, but the seeds and arbores- 
cent branching habit of PL princeps. Variety acaulis of this latter species 
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