inflorescences of Syngonium, though always terminal, appear
to be axillary because after the inflorescences are produced, the
continuation shoot, which arises from the penultimate leaf, displaces
the inflorescence to the side and overtops the inflorescences. Inflorescences
may be solitary or several but are interspersed with bicarinate
bracts called prophylls. A number of species, such as
S. angustatum, S.
podophyllum, and S. macrophyllum,
produce between 6 and 11 inflorescences, whereas many species produce
only 2 inflorescences, and some may produce a solitary inflorescence.
The number of inflorescences that persist and produce mature fruits
is frequently fewer than those that reach anthesis. Some are perhaps
not pollinated or are removed before maturity for some reason.
are nearly always erect and the peduncles are generally obtusely
3-sided or subterete with an obtuse rib on one side. The peduncle,
often relatively short at anthesis, generally elongates substantially
in fruit and becomes recurved, no doubt due to the heavy weight
of the fruits.
unopened spathe is convolute and very tightly closed over the spadix,
generally exceeding the spadix by 1/6-1/3 its length. The spathe
is often conspicuously constricted about midway, separating the
spathe tube from the spathe blade. At flowering time the spathe
unfurls and generally forms a more or less hemispherical cup behind
the spadix. By the time the spathe is fully open, it is generally
white or creamy white, at least on the inner surface of the spathe
blade, though the blade and more frequently the inner surface of
the spathe tube may be colored or at least tinged with red or violet.
In some cases, such as S. neglectum,
the spathe may be reflexed backward, which more fully exposes the
spadix. Though the lower convolute part of the spathe (the tube)
is rarely fully opened, it opens far enough to give easy access
to the pistillate flowers for pollinators. The spathe remains open
for 2-3 days and then recloses over the spadix. The blade portion
of the spathe then soon withers and often promptly falls free. In
other cases the old dried spathe blade persists until later stages
of fruit development. The spadix is divided into three sections.
Staminate flowers occupy most of the apical 4 /5 or more of the
spadix. The lowermost section is occupied by the pistillate flowers.
The basal part of the staminate spadix is made up of sterile staminate
flowers, and these may form a distinct segment, or it merges imperceptibly
with the staminate flowers. Flowers are arranged in a series of
pistillate part of the spadix is generally much narrower than the
staminate part and is generally greenish, though sometimes pale
orange. Length varies from 7-48 mm.
pistillate flower consists of two fused carpels (rarely three).
The flowers are in turn fused into a single unit that later matures
into a syncarp. Each locule usually has one ovule but may rarely
have two (Birdsey, 1955). Ovules are anatropous and placentation
(1955) describes four stigma types: (1) discoid, characteristic
of S. angustatum, S.
auritum, S. chiapense,
and S. podophyllum;
(2) bilabiate (2-lobed or fused together in a ring), characteristic
of S. hoffmannii and
S. salvadorense; (3) orbicular, restricted to S. wendlandii restricted
to S. triphyllum. ;
and (4) cupulate,
staminate flowers are usually roughly the same size as the fertile
staminate flowers but more irregular in shape and generally more
widely spaced. Sometimes the irregularity in shape results from
a fusion of two flowers.
staminate flowers of Syngonium are made up of usually 4 (rarely
2, 3 or 5), nearly sessile anthers. The anthers are fused to varying
degrees into a synandrium. The latter is truncate at the apex and
sometimes depressed medially. The margins of the synandrium are
rhombic, pentagonal, hexagonal, or irregular in outline. Sometimes
the margin is also crenulate. Birdsey (1955) divided pollen grains
into three distinct types: (1) spiny, characteristic of S. angustatum,
S. auritum, S. chiapense, S. macrophyllum, and
S. podophyllum; (2) smooth, characteristic of S.
hoffmannii, S. neglectum, S. salvadorense,
and S. wendlandii; and (3) knobby, characteristic of only