This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
(after J. A. F. Eichhorn, a Prussian Minister, born 1779). Pontederiaceae. Tropical aquatic herbs, grown for showy flowers and interesting habit.
Perennial, floating, rooting at the nodes: immersed leaves on young stems linear; emersed leaves obovate or rounded (or rarely lanceolate), the petioles in some species much inflated and acting as buoys: flowers in a spike or panicle, the scape 1-1 vd.; perianth funnel-shape with a long or short tube; stamens 6, attached unequally in the tube, part of them exserted; ovary sessile, 3-celled; style filiform: fruit a caps, contained in the withering perianth, ovoid to linear. - About a half-dozen species in S. Amer., one reaching Africa
This genus includes the water hyacinth (see Fig. 1384), the famous "million-dollar weed" that obstructs navigation in the stem John's River, Florida, and is a source of wonder and delight in every collection of tender aquatics in the North. The curious bladders made by the inflation of the petioles help the plant to float freely. About flowering time the plant sends down anchoring roots which, if the water be only 3 or 4 inches deep, penetrate the soil. The true hyacinths belong in an allied family (Liliaceae); the pickerel weed, in the allied genus Pontederia, the ovary of which by abortion is one-celled, and each cell one-ovuled, while Eichhornia is three-celled and many-ovuled. The plants of this family have been greatly confused botanically, partly because the fugacious, membranous flowers are not well preserved in dried specimens, and partly because of variation in form of leaves, depending upon whether the plants grow in deep or shallow water, or in mud. The common water hyacinth sends out two kinds of roots, the horizontal ones often thick and fleshy, and apparently for reproductive purposes, the vertical ones long, slender, and clothed with innumerable small, horizontal fibers.
Fig. 1384. Eichhornia crassipes.
The flowers are most beautiful, and the plant is worthy of special cultivation. It is often called a water-orchid, being of such delicate coloring and texture. The plants must be more or less stationary although it is a floating plant, for they will not flower when drifted about by any light breeze or where the water is 2 or more feet deep as is often the case where nymphaeas are grown. A depth of 9 to 12 inches of water is sufficient with a guard to keep the plants in bounds. Good soil underneath is necessary so that the plants will derive some nourishment. They will grow rapidly and flower profusely all through the season, and it may be necessary to thin out the plants, for when too crowded the petioles will become elongated and the plants unsightly. They can also be grown in a tub or tank observing the same method of culture. Propagated by division. (Wm. Tricker.)
A. leaf - stalks inflated: inner perianth-segments not serrated.
Solms (E. speciosa, Kunth. Pontederia crassipes, Mart.). Fig. 1384. Leaves in tufts, all constricted at the middle, bladder-like below, sheathed, many-nerved: scape 1 ft. long, with wavy-margined sheaths at and above the middle; flowers about 8 in a loose spike, pale violet, 6-lobed, the upper lobe larger and having a large patch of blue, with an oblong or pear-shaped spot of bright yellow in the middle; stamens 3 long and 3 short, all curved upward toward the tip. Brazil. B.M.2932 (as Pontederia azurea). I.H. 34:14. A.F. 5:511. variety major, Hort., has rosy lilac flowers variety aurea, Hort., has yellowish flowers
aa. leaf - stalks not inflated: inner perianth-segments beautifully serrate.
Kunth. Leaves on long or short not-inflated petioles, very variable in size and shape: scape often as stout as the leaf - stalk, gradually dilated into a hooded spathe; flowers scattered or crowded in pairs along a stout, hairy, sessile rachis; perianth bright pale blue, hairy outside, inner segments beautifully toothed, the upper a trifle larger, with a heart-shaped spot of yellow, which is margined with white. Brazil. B.M. 6487. G.C. II. 25:17. I.H. 34:20. R.H. 1890:540. - One plant will become 5 or 6 ft. across in a season.
E. paniculata, Spreng. Flowers in a compound spike or panicle, 2-lipped. purple and blue and with large white spots: leaves long-petioled, cordate-acuminate, without petiole bladders: stem 12-18 in.. often several. B.M. 5020 (as E. tricolor).