Typha

Plants of fresh to slightly brackish wetlands, often emergent. Rhizomes at base of erect shoots, mostly horizontal, unbranched, to 70 cm × 5–40 mm, starchy, firm, scaly. Erect shoots vegetative or flowering, single at rhizome apices or arising from shoot bases, thus clustered, unbranched, to 4 m, elliptic in cross section; stems often somewhat compressed distally, aerenchyma absent. Foliage leaves persistent, intergrading proximally with scale leaves, to 15 on each flowering shoot; blade twisted into loose helix, mostly slightly oblanceolate, thickly concave-convex or plano-convex proximally to thinly plane distally (abaxially keeled in the Old World Typha. eleiphantina Roxburgh); mucilage-secreting glands numerous in adaxial surface of sheath and sometimes proximally on blade, colorless to brown, roughly rectangular. Inflorescences: staminate scales shorter than or exceeding flowers; pistillate spikes usually persisting into winter, when dry fruiting flowers often falling in masses; pistillate bracteoles absent or numerous, colorless except for brown apical blade at spike surface, filiform, blade club-shaped to lanceoloid. Staminate flowers: anthers dehiscing longitudinally, 4-sporangiate. Pistillate flowers: pistil hairs colorless and wholly filiform, or apically enlarged and brown, exceeded by stigmas; carpodia obovoid, spongy, bearing rudimentary styles. x = 15.

Discussion

The extensive literature on Typha has been reviewed (C. M. Finlayson et al. 1983; J. B. Grace and J. S. Harrison 1986; J. W. Thieret and J. O. Luken 1996). A modern taxonomic revision is much needed, especially for eastern Asia, adjacent islands, and South America (S. G. Smith 1987); the latest worldwide monograph is that by E. M. Kronfeld (1889). The center of diversity (ca. 6 species) is central Eurasia.

Typha is ecologically important in many fresh to slightly brackish wetlands, often emergent in up to 1.5 m of water. Each spike may produce hundreds of thousands seeds, which are efficiently wind-dispersed and germinate on bare wet soils or under very shallow water. The seedlings rapidly form clones by means of rhizomes in the first season, flower the second season (R. R. Yeo 1964), and often form very large, persistent, often monospecific stands. Some species produce large amounts of biomass, comparable to the most productive agricultural crops. The three species are ecotypically well differentiated in North America (S. J. McNaughton 1966). Some mechanisms of competition between Typha species were studied by J. B. Grace and R. G. Wetzel (1982) and J. B. Grace (1988) (cf. Thieret and Luken 1996; , J. B. Grace and J. S. Harrison 1986).

Common teratological forms are longitudinally split pistillate spikes (caused by parasitic insects), pistillate spikes interrupted by zones of naked axis, and partially merged pistillate and staminate spikes.

Typha species are or have been utilized in numerous ways worldwide (C. M. Finlayson et al. 1983; J. B. Grace and J. S. Harrison 1986; J. F. Morton 1975; V. Ramey 1981; J. W. Thieret and J. O. Luken 1996). Leaves are used for dwellings (walls, roof thatch, floor coverings); for mats, baskets, and other handicraft objects; for caning chairs; and for caulking barrels, boats, and houses. "Fluff" from fruiting spikes is used for tinder and insulation; for dressing burns; and for stuffing pillows, quilts, mattresses, life preservers, toys, and diapers. Young shoot bases, young rhizomes, starch from mature rhizomes, staminate flowers before anthesis, and pollen are all minor sources of food. Typha is valuable as habitat and food for many kinds of wildlife. It is useful for removal of various kinds of pollutants; a potential source of fiber for paper and other products; and a potential source of energy, e.g., for alcohol manufacture. The seeds comprise about 18–20% of an edible oil (69% linolenic acid). Several species are cultivated as ornamentals. The North American species are often sold commercially and planted for wildlife habitat and in wetland restoration.

The larger Typha species and T. ×glauca can be serious weeds in managed aquatic systems worldwide, where they can invade canals, ditches, reservoirs, cultivated fields, and farm ponds; they can be a nuisance in recreational lakes; and they can reduce biodiversity and displace species more desirable for certain kinds of wildlife (J. B. Grace and J. S. Harrison 1986; J. F. Morton 1975; J. W. Thieret and J. O. Luken 1996).

Users of this treatment should be aware of the following: 1) Leaves shrink considerably in width as they dry. 2) Leaf mucilage glands are usually colorless and difficult to see in fresh leaves of all three species early in the season and in Typha latifolia at all stages. They are brown and clearly evident to the unaided eye in mid- to late-season fresh or dried T. angustifolia and T. domingensis and are easily stained (with, e.g., safranin). Brown necrotic spots, apparently caused by feeding arthropods, may superficially resemble mucilage glands. 3) Spikes are commonly poorly developed as a result of drought or other causes; fruiting spike thicknesses given herein are for normal spikes. 4) Except for the presence of mucilage glands on the leaf blades, unique to T. domingensis and its hybrids, the microscopic flower and bracteole structures are generally essential for accurate identification of Typha species and hybrids. This is in part because of changes in the inflorescences during development and in part because of phenotypic plasticity, especially of leaf blade widths. It is often necessary to use forceps to pull a few pistillate flowers out of the spike and observe them with a dissecting microscope at 20 X to 30 X. 5) Pollen is often infested with fungi, which attach the grains together and simulate genetically aborted grains, and the grains of T. angustifolia and T. domingensis often adhere in small groups for no obvious reason.

Hybrids: Putative hybrids among the three North American species have been experimentally produced and occur in most regions of sympatry and have been experimentally produced (S. G. Smith 1967, 1987). Local studies were provided (J. R. Dugle and T. P. Copps 1972; T. M. Tompkins and J. Taylor 1983). Protogyny and slight differences in flowering dates favor interspecific pollination. Hybrid seedlings are likely wherever two species form mixed stands and bare wet soil is available for seed germination and seedling establishment. 1) T. latifolia × T. angustifolia (=T. ×glauca Godr., pro sp.), often called "hybrid cattail," is abundant throughout most of the region of sympatry of the parents except along the southeast coast, where it is uncommon. Almost all plants are putative ff1s which are intermediate between the parental species in all morphologic characters studied and are highly sterile, producing very few or no seeds or viable pollen grains. Fertile or sterile intermediates between T. ×glauca and T. angustifolia occasionally occur, however. In spite of its sterility, T. ×glauca is remarkably successful ecologically. It often spreads by means of rhizomes to form often very large clones and out-competes the parental species, especially in eutrophic, disturbed habitats with unstable water levels (S. W. Harris and W. H. Marshall 1963; S. G. Smith 1987). Unfortunately it has been treated as a species by many authors (e.g., N. Hotchkiss and H. L. Dozier 1949). 2) Typha domingensis × T. latifolia (= T. ×provincialis A. Camus, T. bethulona Costa) is known only from very few collections in Arkansas, California, Florida, Missouri, Nebraska, and North Carolina. All of these are highly sterile putative F1s except for one putative F2, in which the characteristics of the parental species are recombined, from southern California. 3) Typha angustifolia × T. domingensis is known from scattered specimens in Arkansas, California, Kansas, Kentucky, Missouri, and Nebraska. It is not known from the southeast coast, perhaps because of differences between the species in flowering dates. Most plants are highly fertile, and some may be F2 or later generation hybrids. 4) Putative T. angustifolia × T. domingensis × T. latifolia trihybrids are locally common in California and rare in south-central United States. Introgression between the interfertile T. angustifolia and T. domingensis is presumably probably locally common in the south-central U.S. and north-central California, while introgression between T. latifolia and the other two species is probably very uncommon because of hybrid sterility. Published research presumably demonstrating introgression (e.g., N.C. Fassett and B. M. Calhoun 1952) is faulty (S. G. Smith 1967, 1987). The tetraploid T. orientalis of the Pacific Basin may be of hybrid origin (B. G. Briggs and L. A. S. Johnson 1968; S. G. Smith 1967, 1987).

The following key includes the hybrids, which are not further described in the text:

Selected References

None.

Lower Taxa

Typha angustifolia, Typha domingensis, Typha latifolia

Key

1	Pistillate bracteoles absent, or if present then narrower than stigmas and generally not evident at spike surface; stigmas ovate to lanceolate, persistent on mature spikes; pistillate spikes green in flower when fresh, in fruit mostly 19–36 mm thick; carpodia concealed among pistil hairs; compound pedicels on denuded axis 0.6–3.5 mm; staminate scales colorless to brown.	> 2
1	Pistillate bracteoles present, many as wide as or wider than stigmas, evident at spike surface; stigmas linear (to narrowly lanceolate), sometimes deciduous and thus absent from mature spikes; pistillate spikes brown at all stages (or whitish when flowering and fresh); (T. angustifolia sometimes greenish in fruit when fresh), in fruit mostly 13–25 mm thick; carpodia often evident at spike surface among pistil-hair tips; compound pedicels on denuded axis 0.5–0.9 mm; staminate scales brown or straw-colored.	> 4
2	Pistillate bracteoles absent; stigmas ovate to ovate-lanceolate, often blackish when dry	Typha latifolia
2	Pistillate bracteoles present (but generally evident only at 20–30X after removal from spike, resembling perigonial hairs, with brown, enlarged tips narrower than stigmas); stigmas lanceolate, brown when dry; pistillate spikes usually separated from staminate spikes by gap, in fruit mostly 19–25 mm thick; compound pedicels on denuded axis 0.6–2 mm; seeds absent or few; staminate scales brownish; pollen a mixture of tetrads, triads, dyads, and single grains, sometimes mostly single grains.	> 3
3	Mucilage glands absent from blade; pistillate spikes after flowering medium to dark brown, rarely bright orange-brown.	Typha angustifolia x T. latifolia (Typha glauca)
3	Mucilage glands usually present on adaxial surface of blade near sheath summit; pistillate spikes after flowering bright orange-brown.	Typha domingensis x T. latifolia
4	Mucilage glands absent from adaxial surface of blade and generally from central part of sheath near sheath summit; pistillate bracteole tips darker than (or as dark as) stigmas, very dark to medium brown, rounded (to acute), in mature spikes about equaling pistil hairs; pistil-hair tips medium brown, distinctly enlarged at 10–20X magnification; pistillate spikes medium to dark brown; leaf sheath summits with membranous auricles (often disintegrating late in season)	Typha angustifolia
4	Mucilage glands present on adaxial surface of all of sheath and usually about 1–10 cm of adjacent blade; pistillate bracteole tips much paler than to about same color as stigmas, straw-colored to light brown, mostly acute to acuminate, in mature spikes exceeding pistil hairs; pistil-hair tips colorless to usually orangish (or slightly brownish in hybrids), not evidently enlarged, or often with 1 subapical, orange, swollen cell evident at 20–30X; pistillate spikes bright cinnamon- to orange- or medium brown; leaf sheath summits tapered to blade or sometimes with membranous auricles.	> 5
5	Pistillate bracteole blades much paler than to nearly same color as stigmas, straw-colored to mostly bright orange-brown, usually many acuminate; pistillate spikes usually bright cinnamon- to orange-brown; mucilage glands numerous on proximal 1–10 cm of leaf blade	Typha domingensis
5	Pistillate bracteole blades usually about same color as stigmas, light- to medium brown, usually acute; pistillate spikes usually medium brown; mucilage glands often few or absent from leaf blade.	Typha angustifolia x T. domingensis