Mant. Pl. 2: 147. 1771, nom. cons.
Type: Heliconia bihai (L.) L.
Medium to large rhizomatous herbs with Musa-, Canna-, and Zingiber-like habits, forming clones with erect, leafy shoots in groups of few (1 or 2) to many (>50). Pseudostem composed of overlapping sheathing leaf bases of various colors and textures. Leaves usually large, either distichous with all blades lying in a single plane or appearing spirally arranged; petiole short (Zingiber-like), medium length (Canna-like), or long (Musa-like); blade with the base usually unequal on two sides of midrib, cordate to attenuate, the upper surface usually green, the lower surface green to maroon or red. Inflorescence terminal on leafy or leafless shoot, erect, pendent, or nodding, consisting of a usually brightly colored peduncle, rachis, and few (3 to 5) to many (>30) cincinnal bracts; cincinnal bracts distichous or spirally arranged, each subtending a cincinnus of few (3) to many (>30) flowers. Flowers hermaphroditic, each subtended by an opaque or membranous, variously colored floral bract, persistent or decomposing after anthesis; pedicel short (5 mm) to long (2 cm); perianth consisting of two whorls united at base with various degrees of fusion within and between whorls, the calyx with two free abaxial sepals adnate to the corolla except at apex, and one nearly free adaxial sepal usually reflexed at anthesis, the corolla with three petals, connate except for free margins opposite free sepal; pollen-bearing stamens five, the filaments long, linear, attached to base of perianth tube, the anthers 4-loculate, linear, situated at apex of perianth at anthesis, dehiscence longitudinal; staminode one, opposite free sepal, varying in size and shape; pollen large, omniaperturate, oblate to spheroidal, heteropolar with reduced surface ornamentation (Kress, Stone & Sellers, 1983); ovary inferior, three-celled, placentation basal, the ovules solitary, erect, the style filiform, straight or geniculate, the stigma capitate or lobed. Fruits 1- to 3-seeded drupes, usually blue, rarely red or orange. Pyrenes surrounded by stony, roughened endocarp, exarillate; embryo straight; endosperm copious. 2n = 24 (Andersson, 1984).
Heliconias are native primarily in the American tropics from the Tropic of Cancer in Central Mexico to the Tropic of Capricorn in South America, including the Caribbean. A curious disjunct group of heliconias separated by thousands of miles from most other species is found in the Old World tropics. These six species are distributed from Samoa in the Pacific Ocean westward through Fiji, Vanuatu, the Solomon Islands and New Guinea to the central Indonesian island of Sulawesi (Kress, 1990). The means by which these plants reached the South Pacific thousands of years ago is still an unanswered question. These species undoubtedly belong in the genus Heliconia, even though a separate generic name, Heliconiopsis, was once suggested for them.
The taxonomy of Heliconia (Heliconiaceae: Zingiberales: Monocotyledonae) is currently being investigated by a number of South American (e.g., Abalo & Morales, 1982, 1983; Aristeguieta, 1961; Barreiros, 1976, 1980; Emygdio 1975, 1976; Emygdio & Santos, 1987; Santos, 1978), European (Andersson, 1981a, 1985a,b, 1992; Maas, 1985) and North American (Daniels & Stiles, 1979; Kress, 1984, 1989, 1990a,b; Kress et al., 1993; Smith, 1980) botanists. Over 450 botanical names for species, varieties and hybrids of Heliconia have been published. In addition, over two hundred cultivar and common names have been used in the commercial trade and popular literature. Despite all of these names (many of which apply to the same plants), we are still unsure of how many different forms of heliconias exist and a concensus on species boundaries and relationships has not yet been reached. For this reason estimates on the number of species of Heliconia range from 120 to over 400. However, recent progress on enumerating and describing taxa indicates that 200 to 225 species is a good estimate for the genus.
Over the past 100 years several infrageneric classifications of Heliconia have been proposed; each one has been more complex than its predecessor (Kress, 1984). Recently Andersson (1992) and Kress (1995) have proposed an informal and preliminary classification that includes five subgenera and 23 sections. This classification is not based on a thorough phylogenetic analysis and will be modified as additional investigations of evolutionary relationships within Heliconia are completed.
Preliminary classification of Heliconia (pdf).
Ecology and Pollination Biology:
Most species inhabit moist or wet regions, but some are found in seasonally dry areas. Although heliconias attain their most luxuriant vegetative growth in the humid lowland tropics at elevations below 500 meters, the greatest numbers of species (many locally endemic) are found in middle-elevation rain and cloud forest habitats. Few species occur above 2000 meters (Stiles, 1979; Betancur & Kress, 1985).
The most conspicuous members of the genus inhabit open sites in secondary growth along roadsides, on river banks, and in forest light gaps. With increased destruction by man of the tropical rain forest, these species readily invade and colonize the newly opened areas. Other species never attain such extensive vegetative growth and are restricted to the more shaded habitats of the primary forest. These latter species are often locally endemic and are fast becoming extinct as destruction of the tropical forest accelerates.
In the American tropics, hummingbirds are the exclusive pollinators of Heliconia. In contrast, nectar feeding bats and melaphagid birds are the main visitors to the flowers of Old World species. In neotropical heliconias the birds are attracted by the bright red, pink, orange and yellow colors of the bracts and flowers. The length and curvature of the flower tube in many cases reflects the length and curvature of the bill of the pollinating hummingbird. Although each flower is open for only one day, there are usually many flowers per bract and many bracts per inflorescence so that a single plant may be in flower for a long period of time. As the hummingbirds fly from plant to plant probing the flowers for nectar with their long curved bills, pollen is transferred from flower to flower. In this way natural fertilization is achieved and seeds produced.
Common Names, Uses and Notes:
In the neotropicas, heliconias are occasionally used by native peoples as a source of temporary thatch and as ornamentals in villages. In the South Pacific region, the indigenous uses of Heliconia in traditional life are much greater. The use of the leaves and other parts of heliconias in household chores by Asian cultures has led to some speculation that the distribution of these plants into and throughout the region is a result of dispersal by man (e.g., Merrill, 1954). The employment of the leaves in cooking practices as wrappers for foods and covers for stone ovens is widespread and still common today throughout the endemic range of the species in the palaeotropics (Cox, 1980; Kress, 1990). Where heliconias are not native, they have been introduced (e.g., parts of Indonesia) or are replaced by wild or cultivated bananas (Musa) especially for these uses. In Samoa, the fibres in the epidermis of the leaf bases are stripped off and dried for use in straining coconut milk and as a scouring tool (Kress, 1990).
Platanillo, Latin America; laufao, Samoa; paka, Fiji; Fii Rako and Kore in the Solomon Islands; Daun Pisang Hutan, Indonesia (see Kress, 1990).
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