Polypodium grossum Langsd. & Fisch.; Microsorum grossum (Langsd. & Fisch.) S. B. Andrews; Microsorum scolopendria sensu auct., non (Burm. f.) Copel.; Phymatodes scolopendria sensu auct., non (Burm. f.) Ching; Phymatosorus scolopendria sensu auct., non (Burm. f.) Pic. Serm.; Polypodium scolopendrium sensu auct., non Burm. f.
Naturalized laua 'e (see later in this treat-ment for discussion of this name), maize-scented fern Latin grossus, big, or coarse, apparently in reference to the larger fronds and sori as compared with other species in the genus.
Plants medium-sized, terrestrial, epipetric, or occasionally epiphytic. Rhizomes with scattered brown to dark brown scales. Fronds 3-10 em apart, to 75 cm long. Stipes about as long as blades, straw-colored, glabrous except at the bases. Blades deeply pinnatifid, deeply pinnately lobed, ovate or broadly oblong, light to very dark green (some in shady habitats occasionally black), glossy, thick-herbaceous, lobes 2-10 pairs (young plants simple), gradually tapering to rounded or acute tips.
Very common fern forming a ground cover in large areas in lower-elevation forests, especially in disturbed areas, sea level to 600 m, all major islands.
Phymatosorus grossus is native to New Guinea, Australia, throughout the South Pacific, and probably through southern Asia to tropical Africa. First collected in Hawai 'i in 1919 in Kipahulu, Maui, where it was found thoroughly naturalized in many places between Hana and Kaupo. It probably arrived in Hawai 'i in the early twentieth century and is known to have spread rapidly since 1922. This is probably the most common fern, cultivated or naturalized, in urban areas in Hawai 'i. It is found in street plantings, and in home and public gardens where it is used as a border plant or ground cover and as a con-tainer plant.
There is some debate regarding the generic placement of P. grossus (some authors place it in Microsorum). In many publications and checklists reviewing Hawaiian ferns P. grossus has been identified incorrectly as P. scolopendria (Burm.f.) Pic. Serm., a closely related, smaller, mostly epiphytic fern with thinner rhizomes, larger scales, and only five or fewer lobe pairs. Phymatosorus scolopendria has not been collected in the wild in Hawai'i.
The crushed leaves of P. grossus have a pleasant fragrance similar to that of maile (Alyxia oliviformis) and are used as lei mate-rial, sometimes alternated with hala (Pandanus) fruit sections.
There is a widespread and firmly held belief that P. grossus is the laua 'e referred to in old Hawaiian lore as a fragrant plant from Makana and Kalalau on Kaua 'i. It is unknown whether this plant was a fern. All indications, however, suggest that P. grossus is only recently naturalized. No specimens of P. grossus from Hawai'i have been found in collections made from the time of Captain Cook's arrival in 1778 and through the nine-teenth century, despite the fact that during that time there was a "fern craze" and it was fashionable to make extensive fern collections. Hillebrand's Flora of the Hawaiian Islands, published in 1888, treated all known Hawaiian ferns but made no mention of P. grossus, nor did several fern checklists produced before that. The first known collection in the Islands was from Maui in 1919.
The existence of ancient folklore mentioning laua 'e strongly suggests that the common name was attached to a plant other than P. grossus. Pukui (1983) published several sayings in 'Olelo No 'eau referring to the fragrant laua'e of Makana and Kalalau on Kaua'i: Ka laua'e 'ala o Kalalau (Fragrant laua'e ferns of Kalalau); Ka poli laua'e o Makana (Makana, whose bosom is adorned with laua'e ferns); Laua'e o Makana (The laua'e fern of Makana). Some local popula-tions of Microsorum spectrum on Kauai produce a scent similar to maize when dried. These local maize-scented populations of M. spectrum may be the plants referred to. If so, the application of the name laua'e to M. spectrum, known today as pe 'ahi, has apparently been lost to time.
Puanani Anderson-Wong, an ethnobotanist at the University of Hawai 'i, has studied this problem extensively. She reviewed reports of early explorers in Hawai 'i and reviewed many literary references to laua'e in the English and Hawaiian-language litemture of the 1800s.
In addition she examined herbarium speci-mens at the B. P. Bishop Museum. She has concluded that indeed the name laua'e was originally attached to Microsorum spectrum but was applied to P. grossus after its arrival because of its similar scent and sometimes similar fronds. Today, the name laua 'e is firmly attached to P. grossus.
Phymatosorus grossus, a common fern of gardens and low-elevation woodlands, may be recognized by its glossy, deeply lobed fronds arising from long-creeping rhizomes; and sori in 1-2 rows on either side of the midrib that appear raised on the upper surface. Phlebodium aureum, also a large, deeply lobed fern, differs by its thick mat of golden scales covering the rhizome and prominent bluish stipes, rachises, and veins.