Slender, clustering (?always), spiny, pleonanthic, monoecious climbing palms. Stem covered with leaf sheaths, eventually becoming bare, with long internodes and conspicuous nodal scars, the first stem slender, not usually reaching a great height before being replaced by more robust sucker shoots (?always). Leaves pinnate, marcescent; sheath tubular, tightly sheathing, elongate, often tomentose and densely armed with spines in the distal exposed areas or glabrous and/or unarmed; ocrea well developed, armed or unarmed like the sheath, entire or disintegrating into a fibrous network; petiole very short to elongate, adaxially channelled, abaxially angled, usually with reflexed, bulbous-based spines; rachis elongate, usually curved, usually armed with swollen-based, reflexed spines, apically extended into a long cirrus armed with spines and pairs of small to robust, reflexed acanthophylls, acanthophylls absent on juvenile leaves, very rarely absent on adults; leaflets usually ovate, acuminate, often much narrowed at the base into a brief stalk, rather distant, ± regularly arranged or grouped, thin to coriaceous, with a conspicuous midrib and several more slender lateral veins, in Desmoncus cirrhiferus the main rib extended into a long flexuous tendril, margins smooth or armed with short spines, the main rib sometimes bearing spines, indumentum sometimes present in bands and along veins, transverse veinlets sometimes conspicuous. Inflorescences interfoliar, emerging through the leaf sheath mouths, branching to 1 order, becoming ± pendulous, apparently protandrous; peduncle elongate, slender, semicircular in cross-section; prophyll inserted some distance above the base of the peduncle, thinly coriaceous, 2-keeled, tubular, splitting longitudinally on the abaxial face and tattering, only partially exserted, persistent; peduncular bract 1, longer than and inserted far above the prophyll, thick, coriaceous to subwoody, tubular, enclosing the rachillae in bud, later splitting longitudinally, ± persistent, variously unarmed or spiny, adaxially smooth, often pale cream at anthesis, tomentose or ± glabrous abaxially; rachis shorter than the peduncle, bearing few to numerous, ± spirally arranged, flexuous, slender, short to elongate, often somewhat zig-zag rachillae, each subtended by a minute, triangular bract; rachillae very few to numerous, bearing rather distant, spiral, or subdistichous triads except in the distal ca. 1/3–1/5 where bearing paired or solitary staminate flowers, each flower group subtended by an inconspicuous triangular bract; bracteoles minute. Staminate flowers somewhat asymmetrical; calyx cupular, short, ± membranous with 3, low or acuminate, triangular lobes; petals 3, distinct, ± fleshy, ovate-lanceolate, much exceeding the calyx, acute or acuminate; stamens 6–9, filaments irregularly adnate to the petals, the free portion very short or moderate, very slender at the tip, anthers ± rectangular, basifixed, sagittate at the base, latrorse; pistillode minute, conical, or absent. Pollen ellipsoidal, usually with slight asymmetry; aperture a distal sulcus; ectexine tectate, finely perforate, perforate and micro-channelled, and rugulate, aperture margin may be slightly finer; infratectum columellate; longest axis 19–41 µm [5/12]. Pistillate flowers ± globular or ovoid, usually smaller than or equalling the staminate; calyx cupular or tubular, sometimes ± flattened, ± membranous, very briefly trilobed; corolla much exceeding the calyx, tubular, ± membranous, shallowly trilobed or truncate, sometimes minutely ciliate along the margins; staminodes 6, minute, tooth-like, epipetalous; gynoecium ovoid or columnar, trilocular, triovulate, only slightly exceeding the corolla, stigmas 3, fleshy, reflexed, ovule laterally attached, ?orthotropous. Fruit 1-seeded, ± ovoid or spherical, bright red, deep purple, or black, with apical stigmatic remains; epicarp smooth, mesocarp thin, fleshy, endocarp stony with 3 pores slightly distal to the equator. Seed ovoid, with 3 surface hollows, basally attached, hilum basal, circular, raphe branches densely anastomosing, endosperm homogeneous; embryo lateral. Germination adjacent-ligular; eophyll bifid with rather broad, acute segments or pinnate (2 pairs of leaflets in D. costaricensis). Cytology: 2n = 30.