Erect, single-stemmed and moncarpic or branched and polycarpic rosette shrub, the flowering stems up to about 1.5 m high. Diagnostic features of the species include green, 5-9-nerved, linear-ligulate leaves 17-30 cm long and 3.5-6.5 mm wide, and pappus of disk florets mostly 2.5-4.5 mm long. Flowering specimens were collected in August.
This species, now presumed extinct, formerly occurred on E Maui in Koolau Gap and adjacent slopes, and the eastern summit of Haleakala, apparently on the borders of openings in mesic to wet forests at elevations ranging from 1,600 to 2,300 m. It occurred in sites receiving about 100-250 cm precipitation per year.
Two unusual greenswords occurring on Pu’u Alaea in 1989 reportedly possessed vegetative features characteristic of the presumed extirpated species, Argyroxiphium virescens. One of these Pu’u Alaea plants flowered in August, 1989, allowing detailed comparisons with preserved specimens of Argyroxiphium virescens as well as other species and hybrids of Argyroxiphium native to E Maui. These comparisons suggest that the unusual Pu’u Alaea greenswords represent remnants of hybridization between the now presumably extinct A. virescens and the more common Haleakala silversword, A. sandwicense ssp. macrocephalum, that still occurs at and adjacent to this site. Illustrations of the Pu'u Alaea greensword follow.
Last Modification: March 20, 1997
Each "thumbnail" image below is linked to a larger photograph.
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Habit and habitat of putative hybrid involving A. virescens and A. sandwicense ssp. macrocephalum (photo 1989, Pu'u Alaea, E. Maui) |
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Flowering heads and leaves of putative hybrid (A. virescens x A. sandwicense ssp. macrocephalum) (photo 1989, Pu'u Alaea, E. Maui) |
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Portion of leaf of putative hybrid ( A. virescens x A. sandwicense ssp. macrocephalum), note veins visible through layer of hairs (photo 1989, Pu'u Alaea, E. Maui) |
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Flowering heads of putative hybrid (A. virescens x A. sandwicense ssp. macrocephalum), note pale ray florets, (photo 1989, Pu'u Alaea, E. Maui) |
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Flowering head of putative hybrid (A. virescens x A. sandwicense ssp. macrocephalum) (photo 1989, Pu'u Alaea, E. Maui) |
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Disk florets (right) and ray florets (left) from putative hybrid (A. virescens x A. sandwicense ssp. macrocephalum), note virtual lack of pappus (photo 1989, Pu'u Alaea, E. Maui) |