Monday, December 19, 2005

The genus Utricularia (Bladderworts)
Utricularia belong to the Lentibulariaceae family and worldwide there are some 300 species.
19 species have been identified in Queensland and 11 of these are known to occur in the Port Curtis Pastoral District.
The genus name is derived from the Latin word utriculus meaning a small bladder - an appropriate name as species in this genus possess small insect-trapping sacs which may occur on emergent or subterranean or submerged parts of the plant.
These small carnivorous plants may be aquatic or reside in boggy situations beside swamps and waterholes.
The leaves on terrestrial species are very small near ground level or apparently absent while those of the aquatic species are divided into hair-like segments.

Flower colours are usually yellow, white, red, blue or purple but as most plants are quite small they need to be examined closely to be really appreciated. However, some plants congregate into colonies and when flowering can create quite a pleasing splash of colour. The lower corolla lip of most species is comparatively large often with throat markings.

The tiny dehiscent fruits have persistent calyces which often increase with age.
Utricularia trap their prey in small bladders whose walls are equipped with tiny gland-like structures that evacuate the water from inside and create a partial vacuum. Tiny organisms are enticed towards the trapdoor entrance by secreted attractants and/or directional antennae-like appendages. Here, trigger-like sensory hairs, when touched fling the trapdoor open. Prey and water are engulfed within the bladder and with the trapdoor closing behind the digestion stage may now commence. And so, in time, the process repeats itself.

Not much information exists regarding the place of Utricularia in the food chain but green pygmy geese and wandering whistling ducks have been recorded feeding on Utricularia as, no doubt, many other creatures do.

Many Utricularia species may be grown in pots sitting in water and make interesting subjects.
The following are some Port Curtis species and their flower colours - U. aurea (yellow),
U bifida (blue/white), U. biloba (dark blue), U. caerulea (purple/blue/mauve/white),
U. chrysantha (yellow), U dichotoma (deep violet), U. gibba (yellow), U. lateriflora (pale mauve/white/reddish-purple), Uliginosa (blue/white/mauve/violet).
Joel Plumb

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