Typha

''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrush or reedmace, in American English as reed, cattail, or punks, in Australia as cumbungi or bulrush, in Canada as bulrush or cattail, and in New Zealand as raupo. Other taxa of plants may be known as bulrush, including some sedges in ''Scirpus'' and related genera.

The genus is largely distributed in the Northern Hemisphere, where it is found in a variety of wetland habitats.

The rhizomes are edible. Evidence of preserved starch grains on grinding stones suggests they were already eaten in Europe 30,000 years ago.

Description

''Typha'' are aquatic or semi-aquatic, rhizomatous, herbaceous perennial plants. The leaves are glabrous (hairless), linear, alternate and mostly basal on a simple, jointless stem that bears the flowering spikes. The plants are monoecious, with unisexual flowers that develop in dense racemes. The numerous male flowers form a narrow spike at the top of the vertical stem. Each male (staminate) flower is reduced to a pair of stamens and hairs, and withers once the pollen is shed. Large numbers of tiny female flowers form a dense, sausage-shaped spike on the stem below the male spike. In larger species this can be up to long and thick. The seeds are minute, long, and attached to fine hairs. When ripe, the heads disintegrate into a cottony fluff from which the seeds disperse by wind.

General ecology

''Typha'' are often among the first wetland plants to colonize areas of newly exposed wet mud, with their abundant wind-dispersed seeds. Buried seeds can survive in the soil for long periods of time. They germinate best with sunlight and fluctuating temperatures, which is typical of many wetland plants that regenerate on mud flats. The plants also spread by rhizomes, forming large, interconnected stands.

''Typha'' are considered to be dominant competitors in wetlands in many areas, and they often exclude other plants with their dense canopy. In the bays of the Great Lakes, for example, they are among the most abundant wetland plants. Different species of cattails are adapted to different water depths.

Well-developed aerenchyma make the plants tolerant of submersion. Even the dead stalks are capable of transmitting oxygen to the rooting zone.

Although ''Typha'' are native wetland plants, they can be aggressive in their competition with other native species. They have been problematic in many regions in North America, from the Great Lakes to the Everglades. Native sedges are displaced and wet meadows shrink, likely as a response to altered hydrology of the wetlands and increased nutrient levels. An introduced or hybrid species may be contributing to the problem. Control is difficult. The most successful strategy appears to be mowing or burning to remove the aerenchymous stalks, followed by prolonged flooding. It may be more important to prevent invasion by preserving water level fluctuations, including periods of drought, and to maintain infertile conditions.

''Typha'' are frequently eaten by wetland mammals such as muskrats, which also use them to construct feeding platforms and dens, thereby also providing nesting and resting places for waterfowl.

Accepted species and natural hybrids

The following names are currently accepted:

The most widespread species is ''Typha latifolia'', which is distributed across the entire temperate northern hemisphere. It has also been introduced to Australia. ''T. angustifolia'' is nearly as widespread, but does not extend as far north; it may be introduced and invasive in North America. ''T. domingensis'' has a more southern American distribution, and it occurs in Australia. ''T. orientalis'' is widespread in Asia, Australia, and New Zealand. ''T. laxmannii'', ''T. minima'', and ''T. shuttleworthii'' are largely restricted to Asia and southern Europe.

Uses

Culinary

Many parts of the ''Typha'' plant are edible to humans. Before the plant flowers, the tender inside of the shoots can be squeezed out and eaten raw or cooked. The starchy rhizomes are nutritious with a protein content comparable to that of maize or rice. They can be processed into a flour with 266 kcal per 100 grams, and are most often harvested from late autumn to early spring. They are fibrous, and the starch must be scraped or sucked from the tough fibers. Baby shoots emerging from the rhizomes, which are sometimes subterranean, can be picked and eaten raw. Also underground is a carbohydrate lump which can be peeled and eaten raw or cooked like a potato. The plant is one championed by survival experts because various parts can be eaten throughout the year. Plants growing in polluted water can accumulate lead