Abronia

abronia flower
Abronia macrocarpa
Mercer Arboretum & Botanic Gardens


UofAz 229
Abronia vilosa UofAz 229


APMRU plate 51
Abronia ameliae APMRU

Abronia:
Abronia angustifolia UofAz 816 Sand verbena pollen is oblate ca. 26 (P) x 30 (E) µm and tri or tetra-colpate. Its distinguishing characters are the very uneven furrow margins, the coarse reticulation, and the large polar area. Sculpture elements are plainly visible in the lumina of the reticulations, and the muri are ornamented with verrucae - echinae. The size of the muri-ornamentations varies from smaller than the muri to nearly as wide. The collumellae are smaller than the muri or ornamentations.

The pollen of Bougainvillea and Tripterocalyx (sandpuff) is similar, with Bougainvillea having a noticeably thicker tectum, and Tripterocalyx having a smaller polar area and more pronounced furrows.

Plants:
Fam. Nyctaginaceae
Abronia (sand verbena) includes low, trailing annual plants with fragrant pink, white, or yellow flowers with distinct thin bracts, and borne in globular inflorescences. Leaves simple, viscid-pubescent. The pollen morphology of the Nyctaginaceae is highly variable, from periporate to tricolporate, reticulate to echinate.

Pollen light micrograph:
The distinctive coarse reticulation, sculpture elements in the lumina, and large polar area are clearly evident. L-O analysis clearly shows the sculpture elements on the muri.

Pollen scanning electron micrograph (SEM)
Note the broad smooth muri (with elements) in the SEM of Abronia ameliae (above). Also, this SEM shows the highly variable size of the lumina.

Production and Dispersal:
An insect-pollinated species with generally poor production and dispersal. Pollinated by moths in the wild (Williamson et al., 1994). However, the pollen is pollen is occasionally recovered in fossil preparations from archeological and lake sites in the western United States.

Preservation:
Good, the walls are thick.

Fossil Occurrence:
Late Quaternary.

References:
  • Barth, O.M. and Barbosa, A.F. 1972.
    Catalago sistematico dos polens das plantas arboreas do Brasil meridional. XIV - Nyctaginaceae e Phytolaccaceae. Memorias do institituto Oswaldo Cruz. 70(3): 241-259.
  • Nowicke, J.W. 1970.
    Pollen morphology in the Nyctaginaceae. I. Nyctagineae (Mirabileae). Grana 10: 79-88.
  • Nowicke, J.W. and Luikart, T.J. 1970.
    Pollen morphology in the Nyctaginaceae. II. Colignonieae, Boldoeae, and Leucastereae. Grana 10: 79-88.
  • Williamson, P.S., L. Muliani, and G.K. Janssen. 1994.
    Pollination biology of Abronia macrocarpa (Nyctaginaceae), an endangered Texas species. Southwestern Naturalist 39: 336-341.

Links
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