A small but very distinct order, comprising 4 genera and about 250 species. It is remarkable on account of the roots or leaves often being provided with small bladder-like appendages, which catch minute aquatic animals. The single genus found in New Zealand is almost world-wide in its distribution.
1. UTRICULARIA, Linn.
Slender herbs, floating or terrestrial. Leaves of the terrestrial species all radical, inconspicuous or fugacious; of the floating species scattered, multifid with capillary segments, furnished with floating bladders. Peduncles or scapes radical or axillary, either 1-flowered or bearing a few- or many-flowered raceme or spike. Calyx 2-partite; segments entire or nearly so, often enlarged in fruit. Corolla spurred at the base, 2-lipped; upper lip erect, entire or 2-lobed; lower lip larger, spreading, 3–6-lobed, with a palate projecting into the throat and almost closing the flower. Stamens 2; filaments incurved. Style short; stigma unequally 2-lobed. Capsule globose or nearly so, 2-valved or bursting irregularly. Seeds many.
A large genus of world-wide distribution, the species probably numbering close upon 200. With the exception of U. monanthos, which extends to Tasmania, all the New Zealand species are endemic. They are also very imperfectly known, and require a careful study from fresh specimens.
| A. Stems floating. Leaves submerged, multifid; segments capillary. | |
| Stems often several feet in length; branches with the leaves on 1½–3 in. across | 1. U. protrusa. |
| Stems 2–6 in. long; branches with the leaves on ½ in. across | 2. U. Mairii. |
| B. Plants stemless, growing in bogs or wet soil. Leaves all radical, few, small, narrow-linear, entire. | |
| Flowers pale-purple. Upper lip of corolla not 2-lobed; lamina of lower lip broad, entire; spur short, obtuse | 3. U. novæ-zealandiæ. |
| Flowers white. Upper lip of corolla 2-lobed; lamina of lower lip broad, entire; spur long, acute, minutely 2-horned at the tip | 4. U. delicatula. |
| Upper lip of corolla 2-lobed; lamina of lower lip 3-lobed | 5. U. Colensoi. |
| Flowers dark violet-purple. Upper lip of corolla cuneate, retuse; lamina of lower lip very broad; spur short | 6. U. monanthos. |
1. U. protrusa, Hook. f. Fl. Nov. Zel. i. 206.—Stems floating in still water, branched, often extending to a length of several feet, slender, filiform. Leaves numerous, all submerged, spreading, pinnately multipartite; segments many, filiform; bladders numerous, about ⅛ in. long, obliquely ovoid, shortly pedicelled, attached near the base of the segments. "Scape stout, erect, 2–4-flowered. Sepals oblong. Corolla yellow; upper lip 3-lobed; lower broader, subquadrate, its disc protruded, margins recurved. Spur short, obtuse."—Handb. N.Z. Fl. 222.
