Protologue Description: 20. Macrocarpaea tabula fluctivagifolia J.R. Grant, sp. nov. TYPE: PERU. Huánuco: Southwestern slope of the Rio LlullaPichis watershed, on the ascent of Cerros del Sira, at edge of steep embankment near Camp 3 (Laguna), 09º26'S, 74º45'W, ca. 1290 m, ascending shrub, sparsely branched, 10 ft tall, dbh 1.5 in, 15 July 1969, F. Wolfe 12333 (Holotype: F; Isotypes: NA, NY, USM). Fig. 9E-F.
A Macrocarpaeae harlingii J. S. Pringle et M. pajonalis J.R. Grant cui affinis, sed a M. pajonalis foliis ellipticis coriaceis, et a M. harlingii J.S. Pringle inflorescentia graciliori, floribus parvis, et calycibus brevioribus differt.
Unbranched tree, 2.5-4.0 m, glabrous throughout, trunk to 4-10 cm diam., wood solid in trunk, hollow in younger branches, rings prominent, bark thin. Stems terete to slightly quadrangular, solid to hollow, 3-7 mm in diam. just below inflorescence. Leaves oblong, varying to obovate, petiolate, (7-)14-24 cm long. Petioles 1.5-3.0 mm long, robust with slight vagination 1/8 the length of the petiole, interpetiolar ridge 2-5 mm high. Blades (5.5-)12.5-21.5 x (2.5-)4.0-6.3 cm, entire, slightly revolute, dark above and below, lateral veins scarcely visible either above or below, glabrous, thick, leathery-coriaceous; base aequilateral to oblique, cuneate; apex acuminate to acute. Inflorescence a few-branched, open diffuse thyrse, at least 35 cm long, but actually longer since the entire inflorescence doesn't fit onto a single sheet and is cut, so the actual length is unknown; branches 7-31 cm long, 3-5 flowers per branch. Bracts lanceolate, ovate, to elliptic, petiolate, 11-55 x 3-20 mm; base aequilateral, cuneate; apex acuminate to acute; bract petioles 2-6 mm long. Flowers pedicellate, erect; pedicels 15-38 mm long; bracteoles linear to lanceolate, 3-10 x 1-3 mm. Calyx campanulate, 7-8 x 6-8 mm, glabrous, faintly verrucose, ecarinate; calyx lobes rotund, ovate to elliptic, 2.5-3.0 x 3.5-5.0 mm, apex rounded to obtuse. Corolla, pollen, fruits, and seeds unknown.
Name derivation: From the Latin tabula, board, fluctivagus, the surf, andfolia, leaf, for its "surfboard"-shaped leaves. The hyphen in the epithet is to be maintained, according to Articles 23.1 and 60.9 of the ICBN (Greutcr et al., 2000).