A Palynological Study of the Genus Fuchsia (Onagraceae)

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Abstract
The pollen of 76 collections representing 48 of the .apprx. 100 spp. and all 9 sections of Fuchsia was examined in light (LM) and scanning electron microscopy (SEM), and a selected group in transmission electron microscopy (TEM). The pollen of Fuchsia is shed as monads and is mostly 2-aperturate or very rarely 3-aperturate; the exine sculpture is composed of globular elements, or more rarely elongated elements; the viscin threads are segmented, more rarely smooth; the exine is composed of 2 layers, an outer spongy undifferentiated ektexine, and an inner solid, massive endexine. The polyploid sects. Quelusia (8 spp.) and Kierschlegeria (1 sp.) are characterized by 3-aperturate pollen as are several tetraploid species in sects. Fuchsia and Hemsleyella. Three aperturate grains usually occur only in polyploid species; but not all polyploids have 3-aperturate pollen. Two-aperturate grains occasionally occur in both sects. Kierschlegeria and Quelusia, where they represent the condition of the diploid ancestors. The common ancestor of all extant sections of Fuchsia had 2-aperturate pollen, although ultimately, within the Onagraceae, the 2-aperturate condition must have been derived from 3-aperturate pollen. Most species of Fuchsia have a globular-type sculpture element, but sects. Encliandra (6 spp.) and Kierschlegeria have elongated elements, a derived condition. Most species of Fuchsia have segmented-beaded viscin threads, but sects. Schufia (2 spp), Jimenezia (1 sp.) and Kierschlegeria (1 sp.) and some species of sect. Encliandra have smooth viscin threads, another derived condition. A combination of aperture number, sculpture element, and viscin thread morphology could separate the 9 sections of Fuchsia, although palynology provides, at best, only weak evidence for distinguishing sections.

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