Plants growing solitary or in groups or forming rings.
Rosettes 15-25 x 25-35 cm.
Leaf sheaths 3-4 x 4-6 cm.
Blades (12-) 20-30 (-40) x 2-4 cm, recurved, adaxially concave, spinose-serrate, lepidote, greenish, greyish or reddish.
Peduncle present, incl. inflorescence 80- 120 cm x 4-7 mm, erect, perennial, woody.
Peduncle bracts 5-7 cm x 4-7 mm, laxly spinose-serrate, upper ones entire.
Inflorescence 30-50 cm long, compound, branches of 1st , 2nd or 3rd order, perennial.
Primary bracts 10-15 x 4-5 mm, shorter than the sterile base of the partial inflorescence, narrowly triangular to ovate, acute, entire, glabrous or lepidote.
Partial inflorescences up to 25 cm long, laxly flowered spikes, axis visible, branched, 20-50-flowered.
Floral bracts 4-6(-10) x 4-5 mm, much shorter than the sepals, ovate, acute, mucronate, glabrous or rarely with glandular trichomes, brownish.
Flowers (20-) 22-27 mm long, sessile.
Sepals (5-) 8-12(-15) x 4-5 mm, ovate, acute to obtuse, glabrous or rarely with glandular trichomes, yellow to greenish.
Petals 22-28 x 4-6 mm, erect during anthesis or apex slightly recurved, after anthesis slightly spirally twisted, yellow, with greenish apex.
Petal appendages 3-4 mm long, with short fringes.
Filaments 15-18 mm long. Anthers 4-6 mm long, erect, concealed, greenish.
Ovary 4-5 mm long. Style 17-20 mm long, stigma exposed.
Fruits 8 x 6-7 mm. Seeds 2.5-3 (-4) mm long.

Distribution. PERU. Dept. Amazonas, Cajamarca, Lambayeque, La Libertad. BOLIVIA. Dept. Tarija. ARGENTINA. Prov. Jujuy, Salta, Tucuman , Catamarca, Santiago del Estero, La Rioja, San Juan, Cordoba, San Luis, Mendoza. (5deg30'-) 21deg14'-34deg00' S, 63deg09'-69deg06' (-79deg50') W. D. longipetala comprises the widest distribution range among the species of Deuterocohnia and is the only species with a conspicuously disjunct distribution area. The populations from N. Peru are about 2000 km away from those occuring in Bolivia.

Habitat and ecology. Ecoregions: Peruvian Yungas (56), Tumbes/Piura dry forests (93), Maranon dry forests (94), Andean Yungas (64), Chaco savannas (96), Arid Chaco (131), Cordoba montane savannas (134), Argentine Monte (136) and Argentine Espinal (137). At elevations of 250-1500 m a.s.l. Terrestrial, on dry, rocky slopes, open shrub vegetation on sandstone as well as on granite, also on saline soil. Main anthesis from October to February. Hummingbirds are supposed to be the main pollinators.

Etymology. The epithet refers to the long petals.

Affinities. Deuterocohnia longipetala is similar to D. haumanii, but differs in having less densely flowered partial inflorescences, smaller floral bracts and usually glabrous floral parts. Furthermore, D. longipetala has affinities to D. meziana, which exhibits larger rosettes and branches up to 4th order, and which is usually pedicellate. Putative hybrids of both species occur along the border between Bolivia and Argentina. Putative hybrids between D. longipetala and D. haumanii seem to be common in Salta and Tucuman, Argentina.

Notes and comments.
(a) The type specimen in Berlin was probably destroyed during second world war.
(b) There is only a photograph of the type specimen of D. longipetala (F negative 11389) left. The photo provides only little information on the plant, just showing a small, flower-less part of the inflorescence. Therefore an epitype was choosen. This epitype (Hutchison l571) was collected - like the holotype - in Peru, and provides beside parts of the inflorescence, leaves and flowers.
(c) The type locality of D. longipetala was erroneously cited as "Brazil" by Mez (Smith 1956).
(d) Mez noted already in the first description of Deuterocohnia longipetala that Dyckia decomposita might be a synonym. He had only seen the diagnosis, but not the vouchers.
(e) The collection number Venturi 1023 was given to two different collections. One voucher, which is the type for D. longipetala f. uberrima, and another one, which belongs to D. haumanii

GH
. The latter erroneously has also been cited as type by Smith and Downs (1974).
(f) The vouchers Stuckert 11041 and Stuckert 12098 in G both carry a label with D. gracilis Mez. This name has never been published.
(g) Kurtz 119 (CORD!) noted "Paraguay" on the voucher, without precise locality, it would be the only documented specimen of D. longipetala from Paraguay.
(h) Bartlett 19977-A (La Pampa, Hucal, Campo San Pedro, Laguna Veronica, 12 km NW of Bernasconi) (GH!, MICH, US) got probably a wrong label, as noted on the voucher by Cantino (in schedis). Therefore the locality of the specimen cannot be verified. It would be the only collection in the Argentinean Dept. La Pampa.
(i) Wilson 65-690 (US!) notes Bahia (Brazil) as locality (see also Smith and Read 1975), but this seems to be unlikely, probably there was a mix-up of collection data.
(j) Smith and Downs (1974) assigned Kuntze s.n. (Deuterocohnia chrysantha sensu Mez in C.DC. (1896) in part) to D. longipetala. This voucher is assigned to D. meziana in the present revision.
(k) This term "longipetala" was probably chosen due to the distinctly shorter petals of the species belonging to the genus Dyckia. At first, the type specimen of Deuterocohnia longipetala had been assigned to Dyckia.

For further references and specimens seen, refer to 2013 thesis pp174-179

Deuterocohnia longipetala (Baker) Mez, Mart. Fl. Bras. 3(3): 506, pl. 95. 1894; Castellanos, Gen. & Sp. Pl. Argent. 3: 191, pl. 43. 1945.
Dyckia longipetala Baker, Handb. Bromel. 135. 1889.
Puya flava Willdenow ex Baker, Handb. Bromel. 135. 1889; nomen, based on Humboldt & Bonpland 3595 (B).
Dyckia decomposita Baker, Handb. Bromel. 136. 1889. Type. Mendoza, Argentina, Gillies s n (K).
Deuterocohnia chrysantha sensu Mez, DC. Monogr. Phan. 9: 466. 1896; in part, as to Kuntze s n
Deuterocohnia longipetala (Baker) Mez forma uberrima Castellanos, An. Mus. Nac. Hist. Nat. Buenos Aires 37: 495. 1933. Type. North of Dique, 650 m alt, Tucuman, Argentina, Venturi 1023 (GH, LIL).

Desc from S&D
Plant flowering 8-10 dm high; growing in circles.
Leaves 3-4 dm long;
sheaths reniform, 7 cm wide, glabrous, castaneous beneath;
blades 4 cm wide, attenuate to a slender caudate entire apex, covered above with white transparent scales, beneath with cinereous opaque ones, densely serrate with spines 3-4 mm long.
Scape 5-6 mm in diameter, straight, glabrous;
scape-bracts linear-triangular, serrate, the upper shorter than the internodes.
Inflorescence laxly paniculate, many-flowered; axes subferruginous tomentellous or glabrous;
primary bracts minute, about equaling the buds;
branches spreading, slender, simple or compound, 10-20 cm long, very laxly flowered.
Floral bracts very broadly ovate, apiculate, 4 mm long;
flowers erect, sessile, 17-25 mm long.
Sepals strongly asymmetric, ovate, obliquely truncate, 8-12 mm long, few-nerved;
petals 25-28 mm long, yellow with a green spot at apex, equaling or exceeding the stamens;
anthers 4-6 mm long, green.
TYPE. Humboldt & Bonpland 3595 (holotype, B; photo 11389, F), Rio Maranon, between Rio Chinchipe and Jaen, Cajamarca, Peru, Aug 1802. Erroneously cited as "Brazil" by Mez.
DISTRIBUTION. Dry rocky slopes, 400-2100 m alt, northern Peru to northwestern Argentina.
PERU. CAJAMARCA: Tembladera to Llallan, Contumaza, Weberbauer 3 781 (! Mez); 17 Aug 1952, Ferreyra 8605 (USM); Olmos, 8 Oct 1954, Rauh & Hirsch P-453 (US); Lac, Jaen, 4 Oct 1957, Hutchison 1571 (UC, US). AMAZONAS: Rio Maranon by Tupen, Luya, Jan 1905, Weberbauer 4798 (B, photo 11389, F); Pongo de Rentema, Rio Maranon, Bagua, 3 Mar 1961, Ferreyra 14218 (US, USM). BOLIVIA. SANTA CRUZ, Cercado: Santa Cruz, May 1892, Kuntze s n (NY); Cordillera: Tareira, Lagunillas, 1000 m alt, Cardenas 2850 (GH); Valle Grande: Comarapa, Nov 1947, Cardenas 4007 (US). TARIJA, Gran Chaco: Villamontes 21 Oct 1918, Pflanz 943 (M); 14 Oct 1927, Troll 492 (B, M); Palo Marcado, 2 Oct 1927, Troll 190 (M). ARGENTINA. JUJUY, El Carmen: Puesto Viejo, 4 Mar 1937, Castellanos s n (BA); San Pedro, 29 Sep 1938, Eyerdam & Beetle 22312 (GH); 16 Oct 1964, Cabrera & Fabris 16047 (LP); Abra de Santa Laura, 29 Oct 1964, Cabrera 16389 (US). SALTA, Oran: Quebrada de Yacu:, 3 Feb 1925, Schreiter 3610 (LIL); Agua Caliente, Candelaria, 17 Oct 1927, Venturi 5483 (MO, MVM); Tala Pampa, Oct 1948, Cardenas 4218 (GH). CATAMARCA: Kurtz 4319 (M); La Paz: Micaschistas de Recreo, 16 Jan 1890, Kurtz s n (CORD); 6768 (CORD, US); Alto de Choya, Dec 1910, Castillon 14114 (LIL); Andalgala, 15 Oct 1916, Jorgensen 1580 (BA, LIL, SI, US); 23 Oct 1933, Peirano 9902 (F); Tinogasta to La Puntilla, 7 Feb 1930, Schreiter 6369 (LIL); Cuesta de la Chilca, 3 Jan 1930, Schreiter 6418 (BA, LIL, UC); Sierra de Gracian, 16 Jan 1940, Castellanos s n (BA, LIL); La Quebrada, Dimitri & Piccini s n (BAB); Cuesta de la Negrilla, Schickendantz 288 (CORD). TUCUMAN: Tucuman, Oct 1916, Hauman 1112 (GH); Cadillal, Rio Sali, 11 Nov 1917, Schreiter s n (MVM); Famailla, Quebrada de Lules, Lillo 2328 (LIL); Nov 1919, Schreiter s n (LIL); Barrancas, Rio Tapia, Schreiter 803 (MVM); Vipos, 28 Oct 1923, Schreiter s n (LIL); Trancas, Vipos, Venturi 2496 (US); Tipa, Jorgensen s n (BAB); Las Arcas, Tafi, 26 Dec 1926, Venturi 4835 (US); Escaba, Rio Chico, 24 Nov 1952, Petersen & Hjerting 632 (C). SANTIAGO DEL ESTERO, Ojo de Agua: Cerro de la Cruz, 29 Nov 1944, Balegan 157 (LIL); Sierra de Guasayan, Cerro Mogote, 29 Nov 1943, Castellanos s n (BA). LA RIOJA, Lavalle: Las Trancas, 17 Jan 1906, Kurtz 13171 (CORD); Independencia: Aguadita, Sierra de los Llanos, 3 Dec 1906, Kurtz 14118 (CORD); Los Colorados, 11 Jan 1964, Giusti & Valla s n (BAA); San Martin: Minas, Stuckert 17183 (CORD); Chilecoit, 28 Jan 1927, Parodi 7759 (BAA); Dique Los Sauces, 16 Feb 1944, Parodi 14860 (BAA); Sierra de Ulta, Agua del Medio, 3 Feb 1940, Castellanos s n (BA); Sierra Brava, 17 Feb 1940, Castellanos s n (BA). SAN JUAN: Quebrada del Zonda, 28 Feb 1926, Castellanos s n (BA, US); Jachal, 28 Feb 1937, Spegazzini s n (BAB); dep. Caucete, Nov 1941, Rodrigo 2856 (LP); Dique del Valle, 12 Dec 1963, A. Hunziker 16663 (CORD). MENDOZA: Cerros de Chaycedos, Paramillo de Mendoza, Miers 1098 (BM); Mendoza, Cerro Pilar, 2 Feb 1901, Speggazini s n (BAB); Cacheuta, 25 Dec 1906, Carette s n (SI); Jan 1908, Hauman 1114 (GH); 17 Jan 1908, Spegazzini s n (BAB); 30 Nov 1913, Sanzin 269 (SI); Las Heras: Punta de Las Lajas, 8 Dec 1944, Semper 181 (LIL). SAN LUIS: El Totoral, Bajo de Velis, Sierra de San Luis, 19 Feb 1895, Kurtz 8574 (CORD); Ochoa, Nov 1902, Stuckert 12089 (G); Alto Pencoso, Feb 1914, Bruch & Carette s n (LP); Nogoli, 9 Feb 1925, Castellanos 25/627 (BA); Sierra Varela, 22 Dec 1925, Castellanos 25/2784 (BA); Sierras del Gigante, 15 Nov 1926, Castellanos 26/2040 (BA); La Calera, 31 Jan 1963, Hunziker & Maldonado 16266 (CORD). CORDOBA, Cruz del Eje: Las Higueras, 11 Dec 1885, Kurtz 2827 (CORD); Cerros Minas, 21 Dec 1889, Stuckert 6669 (CORD); Rio Seco: Cerro Colorado, 12 Nov 1950, A. Hunziker 8498 (CORD); Taninga to Los Tuneles, 6 Dec 1958, Boelcke 7740 (BAA); Punilla: Los Cocos, Capilla del Monte, Hauman 1115 (GH); Valle de Punilla, Jan 1917, Hosseus 53 (CORD); Sierra Chica, La Falda, 2 May 1917, Osten 10583 (MVM); Villa Carlos Paz, 24 Nov 1949, Palacios 4180 (LIL); Capilla del Monte, De la Sota 3586 (LIL); Co16n: Pan de Azucar, 1 Dec 1890, Kurtz 6969 (CORD); Dique, Dec 1891, Kuntze s n (NY); Casa Bamba, 30 Dec 1949, De la Sota 1415 (LIL); Santa Maria: Malagueno, 30 Jan 1899, Stuckert 6334 (CORD) Ochoa, 25 Nov 1902, Stuckert 12089 (CORD); 2 Nov 1906, 1614 7 (CORD); San Javier, Yacanto, Mar 1921, Molfino s n (BAF); Calamuchita: Potrero Arroyo Calmayo, 6-11 Nov 1895, Bodenbender in bb. F. Kurtz 8788 (CORD); Cuesta San Ignacio, 25 Dec 1901, Stuckert 11041 in part (CORD); Quinta, 10 Jan 1902, Stuckert 11041 in part (CORD); without locality: Lossen 255 (BH, GH). LA PAMPA: Campo San Pedro, Laguna Veronica, 12 km northwest of Bernasconi, 18 Apr 1943, Bartlett 19977-A (MICH, US).

Protologue
Deuterocohnia longipetala (Baker) Mez forma uberrima Castellanos, An. Mus. Nac. Hist. Nat. Buenos Aires 37: 495. 1933.
A typo differt pannicula expansa ramulis lateralibus floribundus et floribus majoribus (sepala 12 mm long., petala 26-28 mm long.)
Type. North of Dique, 650 m alt, Tucuman, Argentina, Venturi 1023 (GH, LIL).

Smith & Read in Phytologia 30(5): 289-90. 1975
6-1. DEUTEROCOHNIA LONGIPETALA (Baker) Mez, Mart. F1. Bras. 3 (3): 506, pl. 95. 1894; L. B. Smith & Downs, Fl. Neotrop. Mon. 14: 233, fig. 86. 1974.
BRAZIL: BAHIA: Arid habitat between the Espirito Santo boundary and Feira de Santana or perhaps Salvador, but without exact locality, September-October 1965, R. G. & C. Wilson 65-690 (US), cultivated and flowered in Costa Rica in 1972; Read & Daniels 74-97, cultivated from Wilson 65-690 (US).
Wilson is positive of the origin of this specimen and although it is a tremendous disjunct range, the Peruvian disjunct of the species is considerable and there are other instances.
In an attempt to accurately identify this newly reported collection certain characters were given careful consideration as perhaps of specific importance. However, it was determined that sepal margins varied from serrulate in this specimen and those of Peru and Bolivia to completely entire in the Argentine specimens. Sepal length proved to be quite variable also, as did the relationship between sepal length and internodes.
Considerably more field work is required in order to clarify the distinctions between D. longipetala and D. meziana.

Protologue
24. Dyckia longipetala Baker, Handb. Bromel. 135. 1889.
Leaves not seen. Inflorescence a panicle with a slender terete woody rachis and branches and long slender laxly spicate branchlets; flower-bracts ovate, 1/8 in, long. Sepals oblong, obtuse, glabrous, 1/3 in. long. Petals oblanceolate-unguiculate, an inch long. Stamens nearly as long as the petals; anthers linear, 1/6 in. long. Style protruded beyond the tip of the petals, nearly an inch long.

Hab. Banks of the Maranon, Bonpland 3595 ! (Herb. Reg. Berol. named Puya flava). Protologue
25. Dyckia decomposita Baker, Handb. Bromel. 136. 1889. Type. Mendoza, Argentina, Gillies s n (K).
Leaves unknown. Lower branch of panicle with several simple moderately dense erecto-patent branchlets 2-5 in. long; rachis stiff, slender, glabrous; flower-bracts ovate, acute, the lower 1/6 in. long. Calyx 1/4 - 1/3 in. long; sepals very rigid, oblong, obtuse, glabrous, much imbricated. Petals more than twice as long as the calyx; blade lanceolate, acute, 1/12 – 1/8 in. broad. Stamens as long as the petals; filaments filiform. Style a little overtopping the petals.

Hab. Argentine Republic; province of Mendoza, Gillies! (Herb. Kew). Cerros de Chayados, Miers 1098 ! (Herb. Mus; Brit.). A very distinct plant, of which, unfortunately, the material is incomplete.