Trematolobelia macrostachys (Hook. & Arnott) Zahlbr.

Genus: Trematolobelia

Range: O'ahu (Ko'olau only), Moloka'i and Maui (East and West); mesic to wet forest, 550-1,725 m. Note that the species on Mt. Ka'ala were segregated by Lammers (2009) to T. kaalae and some populations from Moloka'i are now T. rockii.

Growth form: Treelet, 1-4 m tall.

Etymology: macro- (long-) stachys (spike / raceme). The specific epithet was given by Hooker and Arnott from a collection brought back by Lay and Collie from the Beechey expedition. The type specimen in Kew has no information other than the name (Lobelia macrostachys) and the location (O'ahu). However, Hooker and Arnott's description includes "racemo simplici terminali longissimo." and Geoge Don gives it the common name of long-spiked Lobelia.

This species is single-stemmed up to 4m tall with the stem dense with leaf scars. The leaves are clustered at the top of the stem and 5-20 flowering racemes one half a meter long are held horizontally to sub-erect forming spokes of a circle crowning the plant. The flowers are red and positioned secund on the raceme.

How to identify: The other Trematolobelia are single island (volcano) endemics, whereas this species is found on O'ahu, Maui and Moloka'i. On Moloka'i, Trematolobelia rockii (presumed extinct) flowers in the late spring, whereas T. macrostachys flowers in the fall. On Maui, the only reported species is T. macrostachys and finally, in the Ko'olau Range of O'ahu, T. singularis has only a single, erect raceme versus multiple horizontal racemes for T. macrostachys.

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