downloads/Killip 2.pdf - Passion Flowers

AMERICAN PASSIFLORACEAE 573
free filaments, the inner tubular in the lower part, cleft above into
floccose, crispate threads or into segments margined with such
threads; operculum none; stamens 8, equal, hypogynous, free except
at the very base; anthers linear or linear-oblong, versatile; ovary
subsessile or short-stipitate, with 4 parietal placentae; styles 4,
united below the middle, exserted; stigmas reniform-capitate; fruit
globose or ovoid, the pericarp coriaceous; seeds 8 to 10, large, with a
parchment-like covering.
TYPE SPECIES: Dilkea retusa Mast.
This genus apparently is confined to the little explored recesses
of the Amazon basin, and our knowledge of it is still too imperfect to
permit of more than a tentative treatment of the species. Although
the genus itself is a well marked one, readily recognized among
Passifloraceae by the conspicuous fringe of pale, crispate hairs on the
second series of corona filaments, the species are for the most part
poorly defined. Dr. Ducke, who after many years of travel in the
upper Amazon region is more familiar with the living plants than
anyone else, has recently made the interesting suggestion to me
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that Dilkea is a monotypic genus. I am inclined to think that
further study and collecting will show that the four last species of the
present treatment should be merged in one; the key to these, it will
be observed, is a weak one. Dilkea parviflora, however, seems
clearly distinct.
In describing Dilkea Masters treated two species, D. retusa and
D. acuminata, and in the Flora Brasiliensis he added a third one,
D. Wallisii. A fourth species was described by Barbosa Rodriguez
in 1891, and a fifth one is proposed in the present paper.
According to Masters' illustration in the Flora Brasiliensis
(pi. 106), P. retusa, P. acuminata, and P. Wallisii appear to have
distinctive leaf outlines, but Ducke has observed (Archiv. Jard. Bot.
Rio de Janeiro 3: 222. 1922; 5: 174. 1930) that D. Wallisii has heteromorphic
foliage, and his No. 21307 shows this.
Masters' illustrations show rather prominent glands near the
middle of the petioles, but in neither his generic nor his specific
descriptions does he mention the presence of petiolar glands. In the
material I have examined, including the types of two of Masters'
species, glands normally are not present, though occasionally one or
more of the petioles may bear a pair of scarlike glands.
Masters' description of the flower tube as cylindric, with the
petals borne at its throat and the corona near its middle, is not substantiated
by the specimens I have at hand. At first the sepals are