MCDERMOTT, MATTHEW and DOUGLAS W. DARNOWSKI.* Department of Biology, Washington College, 300 Washington Avenue, Chestertown, MD, 21620, USA. - Analysis of growth requirements of locally rare bladderworts (Utricularia spp.; Lentibulariaceae).
As an initial study of carnivorous plants in Great Swamp, Kent County,
Maryland, a locally-rare setting, several species of bladderworts were
identified and their preference for particular sites studied in the
wild and in the laboratory. One species, Utricularia
geminiscapa (Lentibulariaceae), which was not previously
identified in lists for Great Swamp, grew sparsely in addition to
three species (U. macrorhiza, U. gibba, U. intermedia)
previously known from this site. These latter three occurred in
abundance, though U. intermedia grew in highly specific
locations with shallow water and moderate shade. Conditions such as
light levels and concentrations of various inorganic components of the
aquatic environment were recorded over a period of six weeks, during
which time the bloom of U. macrorhiza peaked and then waned
while U. gibba began to bloom. Both sites favored and sites
disfavored by these various species were examined for correlation with
plant growth. To the same end, samples of several species were also
cultivated under conditions in the laboratory chosen to mimic
conditions in favored or disfavored sites in the wild. In particular,
levels of [CO2] and light were studied as they affected various growth
parameters. Levels of [CO2] and light in Great Swamp seemed to be best
for either increase in length or trap production for at least two of
the species studied.
Key words: bladderwort, carnivorous, CO2, Lentibulariaceae, light, Utricularia