The Gurania Pages
Page 4
Amanda K. Neill

Although Gurania and Psiguria certainly are conspicuous plants, there are not many recorded human uses for these genera.  Those uses are often medicinal, as most fruits have an unpleasant or bitter taste.  However, to many other species, these are very important food sources.  Many Heliconius butterflies and hummingbird species rely on the pollen or nectar produced in the flowers, and these interactions have been the focus of past studies.  The dispersal of fruits and seeds is a greater mystery.  Some species' fruits are distributed by bats in the genus Phyllostomus.  Studies have shown that bats are attracted by the smell of the ripe fruit, and also echolocate the clusters of fruits conveniently hanging far below tree branches.  This does not explain the dispersal of species with showy yellow and orange fruits, and it is hypothesized that birds are the agents of dispersal in those cases.  Possible culprits are Trogons, Bellbirds, and perhaps Quetzals.  Numerous invertebrates also prey on Gurania and Psiguria, including Blepharoneura flies (Tephritidae) (see Marty Condon's "Flies Without Names" page).

Over 100 species names have been published in the genus Gurania in the last 150 years.  There are no keys to identification that cover the entire range of the genus.  Staminate herbarium specimens far outnumber specimens of the more difficult-to-reach pistillate inflorescences, and only rare specimens include both sexes.  As already stated, the leaf shape on one plant can vary widely, enough to warrant differing species determinations on duplicate specimens of a single collection.  There is a definite need for monographic studies of both Gurania and Psiguria, to allow identification and cataloging in the many floristic efforts underway in the neotropics, and to clarify coevolutionary relationships in associated organisms.

My fascination with Gurania and Psiguria is based in these diverse and charismatic ecological interactions, and in the morphological variations by which these genera have adapted to these interactions.  I am using microscopic and macroscopic morphological characters, geographic distributions, molecular sequencing, and field observations, combined with ecological data, to produce a monograph of Gurania at the New York Botanical Garden.

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Selected Links

Amanda Neill's homepage
Larry Gilbert's Laboratory at the University of Texas at Austin
Marty Condon at Cornell College, Iowa
The Cucurbit Network
The New York Botanical Garden

Selected References

Condon, M. 1984. Reproductive biology, demography, and natural history of neotropical vines Gurania and Psiguria (Guraniinae,
    Cucurbitaceae): a study of the adaptive significance of size related sex change. Ph.D. dissertation, University of Texas, Austin.

Condon, M. and L.E. Gilbert. 1988. Sex expression of Gurania and Psiguria (Cucurbitaceae): Neotropical vines that change sex. Amer.
    J. Bot. 75:875-884.

Condon, M. and L.E. Gilbert. 1990. Reproductive biology and natural history of the neotropical vines Gurania and Psiguria. In Biology
    and Utilization of the Cucurbitaceae (D.M. Bates, R.W. Robinson, and C. Jeffrey, eds.). Cornell University Press, Ithaca, NY.

Feisinger, P. and R.K. Colwell. 1978. Commmunity organization among neotropical nectar feeding birds. Amer. Zool. 18:779-795.

Gilbert, L.E. 1972. Pollen feeding and reproductive biology of Heliconius butterflies. Proc. Natl. Acad. USA 69:1403-1407.

Photo by John Janovec.
Last updated 24 May 2001 by Amanda Neill.