THE EDIBLE PASSION FRUIT IN HAWAII 6 
and several kinds of humming birds, are able to get it. These pollen 
carriers are of such size that the parts of their bodies to which pollen 
adheres will come in contact with both stamens and the stigmatic 
parts of the pistil. These pollen carriers, in their eager quest for 
nectar, visit many flowers frequently, and hence naturally have 
ample opportunity to carry pollen to many receptive stigmas. In 
Hawaii, carpenter bees are frequently seen visiting passionflowers, 
moths are rarely seen, and humming birds apparently do not exist. 
It is believed that dry sunny conditions, w T ith breezy trade winds, 
also aid in transmitting pollen from one flower to another and from 
stamens to pistils of the same flowers. There are, however, failures 
in pollination when both carpenter bees and breezes are present. 
Even hand-pollination has failed. These failures have been reported 
from many countries where Passifloras are grown. Investigation has 
shown that some species often have protandrous flowers, that is, the 
pollen of the anthers is ripe before the stigmas are ready to receive 
it. The protandrous habit, no doubt, is a natural condition' of a 
number of Passifloras and of some other kinds of plants. It is be- 
lieved to have proven a means of bringing about cross-pollination of 
species and possibly of varieties. The habit, in the case of the Passi- 
flora, is closely associated with unusual form of floral parts, par- 
ticularly of the essential organs (stamens and pistils). 
The yellow passion fruit (P. edvMs fldvicarpa) is the most im- 
portant and the most variable of the passion fruits in its pollination 
habits. Faulty pollination is undoubtedly a frequent cause of scant 
fruit production. 
The bell-apple (P. lawvfolia) is a prolific bloomer but invariably 
fails to produce fruit in proportion to the number of flowers. 
The large purple strain of P. edulis, grown at the Hawaii Experi- 
ment Station, is a scant bearer, and some of the fruits are also defec- 
tive in having a portion of the interior without seeds and edible pulp, 
possibly due to faulty pollination. The size of fruit and defective 
pollination habits are apparently transmitted in this seedling strain. 
The unfruitfulness of certain Passiflora species is not peculiar 
to the Hawaiian Islands. Macmillan (.9, p. 267) states that P. lauri- 
fol'm has been in cultivation in Ceylon and parts of Asia proper 
for many years without fruiting. Popenoe (18, p. 24.2) notes that 
P. edulis, in some countries, fails to produce fruit. It has been 
stated (14) that the large purple variety or strain of P. edulis 
is a shy bearer. 
The giant granadilla (P. quad ran gularh) . when grown in South 
Queensland, Australia, is reported by Barnes (J, p. 675) as often be- 
ing a shy bearer, and this he attributes to the flowers being protan- 
drous. He suggests that in the absence of insects to transmit the 
pollen from young blossoms to fertilize the older flowers, hand- 
pollination be practiced. Protandrous conditions of the giant gran- 
adilla have not been reported in Hawaii. However, cultivation of 
this species is rare and but little study of it has been made. 
Both the yellow passion fruit and the bell-apple grow mostly 
at altitudes below 500 feet in Hawaii. A few trials have been made 
at the Kona substation, altitude 1,500 feet, and in cooperation with 
growers on the Island of Hawaii, at 1,000, 1,200, and 1,500 feet, but 
a fair set of fruit is rarely produced. Heavy yields have been pro- 
