Rapateaceae Dumort.

Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://creativecommons.org/licenses/by/3.0

Morphology General Habit

Herbs caespitose, perennial, often in swampy areas, frequently mucilaginous; rhizome short, erect or prostrate

Morphology Leaves

Leaves distichous, spirodistichous or rosulate, often equitant, rarely petiolate (Rapatea longipes Spruce ex Körn., Saxo-fridericia aculeata Kornicke), sometimes with margin aculeate (Saxo-fridericia aculeata); leaf sheaths developed and invaginating; leaf blades ensiform, lanceolate or linear

Morphology Reproductive morphology Inflorescences

Inflorescences compound, axillary or terminal, capituliform, usually involved by two or more spathes; spikelets few to many, pedicellate or sessile, comprising a single terminal flower surrounded by several sterile bracts; flower monocline, actinomorphic, or slightly zygomorphic, perianth in two differentiated whorls; sepals 3, rigid, papyraceous, or membranaceous, similar to bracts, hyaline at the base, free or connate; petals 3, white, yellow or red, sometimes with blotches, membranaceous, usually connate, with lobes lanceolate, ovate or obovate; stamens 6, adnate to the corolla tube, anthers basifixed, introrse, sometimes with terminal appendages, dehiscencing by 1, 2 or 4 apical or subapical pores or short slits; ovary superior, carpels 3, locules 3; ovules anatropous, 1-8 per locule, basal or axile placentation; stylus simple, erect; stigma capitate; loculicidal capsules

Morphology Reproductive morphology Seeds

Seeds globose, oblong, striated or muricate, chalky endosperm .

Note

Notes on delimitation: Rapateaceae is placed within the order Poales (APG III, 2010) as a Bromeliaceae sister group.  Mayacaceae is close to Rapateaceae in some studies because both have poricidal anthers. Rapateaceae is organized in 5 tribes: Stegolepidieae, Schoenocephalieae, Saxofridericieae, Monotremaeae, Rapateeaea. Number of genera: 17 genera with 16 ocurring in the Neotropics ~100 spp. Amphiphyllum Gleason (1 sp.)  - Brazil and Venezuela. Cephalostemon Schomb.(5 spp.) - Brazil, Bolivia, Suriname and Venezuela. Duckea Maguire. (4 spp.) - Brazil, Colombia  and Venezuela. Epidryos Maguire. (3 spp.) - Brazil, Colombia, Equador, Guyana, Panamá  and Venezuela. Guacamaya Maguire. (1 sp.) - Colombia and Venezuela. Kunhardtia Maguire. (2 spp.) - Venezuela. Marahuacaea Maguire. (1 sp.) - Venezuela. Monotrema Koern. (5 spp.) - Brazil, Colombia and Venezuela. Phelpsiella Maguire. (1 sp.) - Venezuela. Potarophytum Sandw. (1 sp.) - Guyana. Rapatea Aubl. (27 spp.) - Brazil, Bolivia, Colombia, Ecuador, Guyana, French Guyana, Peru, Suriname and Venezuela. Saxofridericia Schomb.(7 spp.)  -  Brazil,  Colombia, French Guyana, Guyana, Suriname,  and Venezuela. Schoenocephalium Seub. (4 spp.)  - Brazil, Colombia and Venezuela. Spathanthus Desv. (2 spp.) Venezuela, Brazil, Colombia, Guyana and French Guyana. Stegolepis Klotzsch ex Koern. (33 spp.) - Brazil, Guyana, Panamá and Venezuela. Windsorina Gleason. (1 sp.) - Guyana. The species usually occurs in habitats with humid soil.

Distribution

Rapateaceae is restricted to the Neotropics with the exception of Maschalocephalus dinklagei Gilg & Schumann that occurs in West Africa. The center of species diversity of Rapateaceae are the lowlands Guyana Shield and the Amazon. All the family is native in Neotropics, except for the genus Maschalocephalus.

Diagnostic

Distinguishing characters (always present): Mucilage cells, stomatal guard cells dumbell-shaped, uniseriate colleters, inflorescencecapitate and scapose, anthers with pores or short slits, microsporogenesis simultaneous. Amphiphyllum Gleason - Many bracts of the inflorescence, the outer spathaceous, valvate and connate, spikelets few, sessile; the anthers opening laterally and subapical pore. Ovary with a pluriovulate carpel. Cephalostemon Schomb. - Leaves with sheaths brown, invaginating linear blades. Inflorescências globose; bracts linear-lanceolate, conspicuous, green; bactlets setiform, green, with attenuated apex; sepals oval; petals yellow, obovate, apex retuse and apiculate; stamens opening by subapical slit; ovary globose trilocular, uniovular carpel. Capsule with seeds oblong, non striatre, covered with a dense white papillose mass. Duckea Maguire. - Leaves with ample sheaths; linear blades. Inflorescence subglobose to cylindrical, uniflora, bracts linear-lanceolate; bractlets imbricate; sepals lanceolate, connate at base; petals included; 6 stamens with single apical pore; ovary trilocular, uniovulate carpel. Ribbed seeds. Epidryos Maguire. - Leaves with oval sheaths, invaginating, brown; blades broad-linear. Inflorescences multiple, single or with two branches; involucral bracts lanceolate, inconspicuous, imbricate; flowers yellow. Guacamaya Maguire. -Leaves with brown sheath, invaginating, with white hairs; blades green, broad-linear. Inflorescence hemispheric, solitary, red; involucral bracts connate, bivalvate; spikelets numerous patents, sessile, spiral; corolla included with the basis of the petals connate; fillaments adnate at the base, anthers bitec, biporated; ovary trilocular, pluriovulate carpel; seeds not appendiculate. Kunhardtia Maguire. - Single inflorescence; bracts bivalvate;  spikelets sessile and red, elongated, the inferior reflex; sepals free; petals lanceolate; anthers linear,  bitec; ovary with a pluriovulate carpel. Seeds piramidalis, striate, without appendages. Monotrema Koern. - Leaves with connate sheaths; linear blades. Peduncle axillary, 1-2 per axil; inflorescences small, subglobose or elongated, with 1 or 2 bracts lanceolate to ovate; petals yellow, lanceolate; dehiscence of anthers by a single apical pore; ovary pyriform, 3 locules, uniovulate carpel. Seeds oval, white, muriculate, with appendage at the apex. Phelpsiella Maguire - Inflorescence capituliform, pauciflora; Bracts orbicular-oval, margins connate, adpressed, erect; sessile spikelet; yellow flowers; ovary tricarpellate, pluriovulate carpel; anthers biporated, with rounded porous. Rapatea Aubl. - Leaves with brown or hyalinesheath; blades lanceolate or rarely linear. Inflorescence axillary, capituliforme, coplanar or elongated, free or connate spathes at the base, ovate to lanceolate, apex attenuated; spikelets numerous, pedicellate. Flowers pedicellate, sepals connate, lanceolate oval; petals connate at the base, membranous; anthers linear or oblong, 4-locular, dehiscence by terminal or subterminal pore; uniovulate carpel, placentation basal, stigma capitate, papillose. Capsule attenuated. Seeds oblong, ridged. Saxofridericia Schomb.  - Leaves with blades oblong-linear, margin aculeate, apex acute. Peduncles solitary, axillary; involucral bracts foliaceous, oval, bivalvate, sometimes connate at the margins; inflorescence globose or hemispherical; spikelets sessile; sepals free; petals obovate, the clawconnate into a membrane tube; subterminal porous of the anthers, fillaments adnate to the corolla tube; ovary trilocular, pluriovulate carpel, subulate-triangular stylus. Capsule oblong -oboval. Schoenocephalium Seub. - Leaves with brown sheath; laminalinear, apex attenuated. Inflorescence capituliform;  spiklets radiate; bractlets graduate; sepals free to the base; petals lanceolate, enclosed, not open at anthesis, connate claws; 6 stamens, fillaments adnate to the corolla tube, apex cruciform, 4 porous; ovary trilocular, biovulate carpel, styles terete, truncate, minutely circumciliate. Seeds ribbed, prismatic. Spathanthus Desv. - Leaves distichous, blades linear or oblong, apex acute. Inflorescence adnate to bract, only one involucral bract, lanceolate; spikelets numerous, sessile; anthers 4-locular, dehiscing by a single apical toothed pore; ovary trilocular, two aborted carpels, style subbasal. Seedoblong-ellipticstriate. Stegolepis Klotzsch ex Koern. - Robust herb; blades with sheath readily apparent, blades linear, apex acute. Inflorescence capituliform; spikelets sessile. Windsorina Gleason. - Herb glabrate, swamp. Peduncle erect, axillary; inflorescence umbellate, unwrapped; flowers pedicellate; sepals convolute; petals oval, yellow; fillets free twisted after anthesis, anther tetralocular with a subterminal pore. Capsule oval, loculicide, one seed per locule.