The 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.

Inflorescences 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.

The 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 close spirals.

The 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.

Each 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 is basal.

Birdsey (1955) describes four stigma types: (1) discoid, characteristic of S. angustatum, S. auritum, S. chiapense, S. macrophyllum, 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,

Sterile 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.

Fertile 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 S. triphyllum.