U gibba is the easiest aquatic bladderwort to raise. A suspended aquatic, it produces stolons up to several inches long. Leaves are produced singly at intervals about every inch or less, depending on lighting conditions. Bladders most often appear on the leaves, but can be found occasionally on the stolons as well. The effect of this plant is to appear as a floating mass of green hair, and in nature, it can often be overlooked as a mat of algae. The flowers reach 1/2" in diameter and are yellow, it but has not flowered for me in cultivation.
This plant has a global distribution. Various subspecies have been proposed for U. gibba based mainly on the size of the corolla, but Taylor claims that he was unable to construct a key with which to distinguish them. In his 1989 work, he identifies no subspecies.
The following species are all submersed species, meaning that in the wild they will be found anchored to the local substrate. In cultivation, these plants can easily be raised as floating plants, though they grow in a disorganized fashion, and so lose some of their charm.
U. purpurea a beautiful plant. Stolons can reach a couple of feet in length, producing whorls of branching, bladder-bearing leaves every inch or so. Actually, in many descriptions, it is stated that the plants "produce whorls of bladders" only (no leaves), but this is somewhat untrue. The plant definitely has a "bushy" look to it, and such descriptions are probably trying to convey the fact the the leaves are reduced to filiform segments, as opposed to the more obvious leaves of other aquatic bladderworts.
Flowers are dark purple with a large palate, and are approximately 3/4" in diameter. In Eastern Canada, it is the only bladderwort to produce a purple flower. A little difficult to raise, it needs absolutely clean water.
Formerly called U. vulgaris, which now applies only to an almost identical species found in Europe and Asia, U macrorhiza is the largest Canadian Utricularia. It produces extremely long stolons (up to 10 feet long) which produce a mid-rib up to 2" that produces many small branching leaves. It is along the mid-rib and leaves that the bladders are produced. Bladders are typically about 1/4" in diameter, and after a time turn first reddish, then brownish, then finally black. I believe the appearance of black bladders is diagnostic of the species in Canada. In the wild, the plants have a flatter appearance, leaves being produced on one of two sides of the stolon. For some reason, in cultivation, this changes to more bushy growth pattern, leaves being produced anywhere along the stolon. It produces 3/4" inch yellow flowers are in July is an easy species for cultivation.
A lovely and unusual Utricularia, the stolons of U. intermedia can reach a length of 6", with many alternately produced flat, needle-like leaves. The effect is not unlike that for hornwort, and if you don't know what that looks like, then think of a pine tree branch, and you won't be too far off the shape. U. intermedia has a somewhat lighter coloration than other North American species, appearing more lime colored. The large bladders (1/2 cm) are produced on adventitious stolons that usually protrude from the just beneath the leaves. Usually about 10 bladders are produced on each stolon. Flowers are apparently yellow, but I have never seen them. A little more difficult to raise than U. macrorhiza, but not overly difficult either.
The native distribution of this plant is from continental Europe, through Russia, to Japan. U. brehmi looks much like many other floating species of Utricularia. Stolons reaching several inches in length produce half inch, singly forking leaves at half inch intervals. Bladders are generously produced on the leaves, and attain a fairly large size of 1/4 inch or more. The bladders are somewhat elongated in nature, and the hairy guide hairs are as long as the traps. A temperate species which produces turions.
Another fairly large, temperate aquatic bladderwort, this one from Japan. Stolons can reach several feet in length. Multi-branched filliform leaves are produced every quarter inch, and can reach a length of an inch and a half. Small bladders up to 1/8 inch in length are infrequently produced on the leaves. This seems to be one of a number of aquatic Utricularia that often fail to produce bladders in cultivation. Possible causes for this that have been suggested are the following: insufficient lighting, insufficient iron, and lack of albumen in the water. I am currently experimenting to find the cause and possible remedies for this, and will report any findings I might make. Flowers are bright yellow.
Hailing from Southeast Asia, this is the bladderwort you're most likely to find in a pet store, should you ever actually see a bladderwort in a pet store! U. aurea is a fairly "thick" looking plant, whose robust stolons can reach up to three feet in length. Leaves are produced every half inch. The midrib of these leaves are as thick as the stolon and produce a multitude of hairy, sometimes branched leaves. The effect of its growth pattern is to produce a somewhat "skeletal" looking plant. As with U. dimorphanta, this species often does not produce bladders for some unknown reason. Flowers are yellow with a little red speckling on the throat. A tropical plant that needs year round warm temperatures. Easy to raise as long as algae and dirty water are avoided.
As stated above, this plant is virtually identical to U. macrorhiza. Leaves are produced in the same manner, although appear to be produced somewhat closer together than for macrorhiza. Bladders also seem to be marginally smaller, with much less obvious guide hairs. Keep in the same manner as U. macrorhiza.