phytotaxa - Magnolia Press

Subspecific variation:—Rachis spines are less developed in subsp. palustris than in other subspecies,
and in some cases are abaxial and appear short and recurved, almost like those of Desmoncus polyacanthos.
See also notes under D. interjectus.
Although Desmoncus riparius is an older name than Desmoncus palustris, its type specimen ((Desmoncus
riparius Spruce (1869: 156). Atitara riparia (Spruce) Kuntz (1891: 727). Type:—VENEZUELA. Amazonas:
Río Negro, San Carlos de Río Negro, October 1854, R. Spruce 46 (holotype K!)) may be of hybrid origin. A
group of specimens (Clark 7982, Liesner 8940, Spruce 46, type of D. riparius) from Venezuela (Amazonas),
not included in the above description, appear intermediate between subsp. palustris and D. polyacanthos, both
of which occur in this area. These intermediates resemble D. polyacanthos but have scarcely spiny peduncular
bracts and fruit surfaces with Y-shaped fibers. Another specimen (Liesner 6274) is from the same locality but
much smaller and with a non-spiny sheath.
5.5. Desmoncus horridus subsp. prostratus (Lindman) Henderson, comb. & stat. nov.
Basionym: Desmoncus prostratus Lindman (1900: 8). Atitara prostrata (Lindman) Barbosa Rodrigues 1902: 75.
Type:—BRAZIL. Mato Grosso: Santa Cruz da Barra, June 1894, C. Lindman 2827 (holotype S!).
Inflorescences peduncular bracts no data; rachillae 14(11–16); fruits 14.7(14.6–14.7) mm long.
Distribution and habitat:—From 14°45’–15°20’S and 57°11’–62°20’W in Bolivia (Santa Cruz) and
Brazil (Mato Grosso) at 178(150–250) m elevation, mostly in the Pantanal region in gallery forest, forest
patches in savanna, shrubby forest, or semideciduous forest, often in flooded areas (Fig. 7).
Two specimens, not included in the above description, are unusual and may be hybrids. One (Krapovickas
31940) appears intermediate between subsp. prostratus and possibly D. polyacanthos. The second (Cid 4636)
is from the north of the main range of subsp. prostratus and is reported to come from “campo natural cerrado”.
6. Desmoncus interjectus Henderson, sp. nov. (Appendix IV Plate 5)
A speciebus aliis spinis secus costis bracteae peduncularis praedita differt.
Type:—COLOMBIA. Amazonas: Río Yarí, cerca a la desembocadura de la quebrada El Mochilero, 120–200 m, 21 April
1986, G. Galeano, J. Torres, J. Huitoto & B. Plazas 1092 (holotype COL!, isotype NY!).
Plants 6 m tall; stems 2.1(1.7–2.8) cm diameter. Leaf petioles 2.9(1.0–10.5) cm long; rachises 125.0 cm long,
8.2(6.2–11.0) mm wide, the spines usually