The Flowering Plants of Hawaii
Part 51 Agavaceae-Alismataceae
The genus Agave consists of about 220 species distributed throughout the southern United States, western Panama, the Caribbean Islands, and Venezuela. A familiar species to many visitors would be A. americana, the century plant, so-called because it is thought to flower only every hundred years. The hundred year flowering time is exaggerated, but it can take 20 years for this plant to flower. Also known as American aloe, A. americana is a source of mescal (mezcal) and is grown commercially for the production of that liquor.
The only member of the genus on the Hawaiian Islands is A. sisalana (see image), malina, sisal, or sisal hemp. This plant has been cultivated as an important source of fiber in many parts of the world. The form planted is apparently a sterile cultigen of unknown origin (Mabberley, p. 20). Efforts to establish a commercial sisal operation in the Hawaiian Islands failed owing to high labor costs (Manual). Sisal plants can be seen in many parts of the islands, usually in dry, rocky sites. I have seen it growing on the southern slopes of Haleakalä, and on roadsides on eastern Moloka`i where the photograph was taken, and other similar habitats.
By far the most important member of Agavaceae on the islands is Cordyline fruticosa (C. terminalis in some earlier literature) (see image), known in Hawaiian as kï (ti in Polynesian, but a word often used in the Hawaiian Islands as well). Cordyline is a genus of about 20 species of the warm tropics of Australasia, Pacific islands, and tropical America (Mabberley, p. 216-217). This plant is a Polynesian introduction with a variety of uses.
Visitors to the islands who have enjoyed a lü`au would have experienced at least one of the uses for kï leaves, likely one of the most important ones: wrapping food (routinely pork at lu`au) to be cooked underground. The leaves are sufficiently durable that they can be used again with a bit of washing. Cooked food can be stored in kï leaves, house walls can be thatched with kï leaves, and children use them to slide down muddy slopes on kï leaves. Kï is also thought to have protective powers against psychic evil, either by a person carrying leaves to ward off evil, or slapping oneself with a bundle of leaves to exorcize evil already present. A medicinal use of the plant, as a laxative, is described in the short poem: `Ai ke kï, kï, kï: a hi, hi, hi! which translates as: Eat the kï, kï, kï: and run, run, run!.
Several varieties of kï are known that have brightly colored leaves making them attractive in decorative plantings throughout the islands (see image). Decorative kï plants (usually described as ti) can often be found in gardening centers in North America.
According to authors of the Manual Pleomele , known in Hawaiian as hala pepe, is represented on the islands by six endemic species. The array of strap-like leaves arising from the top of the stem is characteristic (see image). The flowers (see image inset) were used in lei making (Krauss, p. 77), while the leaves are used, along with the fern Microlepia strigosa (palapalai), to adorn the hula altar. Estimates of species number range from 40 to as many as 100, according to the Manual. Mabberley includes species of Pleomele within Dracaena, which, as noted above, now resides in Asparagaceae. DNA data support the newer alignment.
Phormium, a New Zealand genus of two species, is represented on some of the Hawaiian Islands by P. tenax (see image), commonly referred to as New Zealand flax. The fibers of this plant are woven into mats by the Maori.
Sagittaria latifolia (see image), commonly known as arrowhead (sagitta is the Latin word for arrow) or swamp potato owing to its edible tuber. This is a North American species that occurs from southern Canada to Mexico and Central America. It is found in the Hawaiian Islands in slow moving streams and other wetlands, including taro fields. The plants illustrated here were growing in a stream flowing through NTBG.