[4] It is very rare in the wild and some of its original habitat has been replaced by sugar cane plantations.

[6] Using cladistic methods, phylogenetic studies of DNA have shown that the closest relative of Munroidendron racemosum is Reynoldsia sandwicensis.

[10] Polyscias racemosa is a small tree growing to 25 ft (7.6 m) tall, with a straight trunk, spreading branches, and smooth, grey bark.

Associated plant species include papala kepau (Pisonia umbellifera), ʻāwikiwiki (Canavalia galeata), ʻilima (Sida fallax), ʻōlulu (Brighamia insignis), alaheʻe (Psydrax odorata), kōpiko (Psychotria spp.

[14] It occurs naturally in only three locations on Kauaʻi: Nounou Mountain, the cliffs of the Nā Pali Coast, and Haʻupu Ridge near Nāwiliwili Bay.

[15] Earl Edward Sherff felt that this species was uniquely distinct from the rest of Tetraplasandra, so he erected a new genus for it, Munroidendron, in 1952.

[18] Sherff separated Munroidendron from Tetraplasandra on the basis of five characters: the absence of umbellules, the arrangement of the flowers in a raceme, the sunken, diamond-shaped pedicel scars, the long, persistence of the subtending floral bracts, and the insertion of the stamens in only one whorl, even when numerous.

William R. Philipson said that Munroidendron "comprises a single species with such a distinct inflorescence and corolla that it can well claim generic status.