Arthrocereus

The Brazilian genus Arthrocereus comprises four species, some of which are in cultivation and fairly well known. Like many groups of the tribe Trichocereeae, however, not enough is known about the natural variation of the cacti in the field. There was some confusion as to the first use of the name Arthrocereus but this has been clarified by Nigel Taylor (1992), who proposed conservation of the name with a new type, A. glaziovii (syn. Cereus glaziovii), with the original type, C. mi-crosphaericus, now recognized as a synonym of Schlumber-gera microsphaerica.

Alwin Berger described Arthrocereus in 1929, deriving the

Arthrocereus Glaziovii

Arrojadoa rhodantha

Arrojadoa dinae subsp. dinae Arrojadoa penicillata

Arrojadoa rhodantha

Arrojadoa dinae subsp. dinae Arrojadoa penicillata

Esculturas Para Jardin

Arthrocereus melanurus subsp. melanurus, photograph by Nigel Taylor

Arthrocereus glaziovii, photograph by Gordon Rowley word from the Greek arthro-, jointed, thus jointed cereus. There are four species and three subspecies, all relatively small plants with several jointed branches that are usually upright. Flowers open at night in summer, are long funnel-form, and have only a few scales on the pericarpels and floral tubes though they possess white wool and hairlike spines. Fruits are usually globose, green, and have small scales and hairlike spines.

Arthrocereus A. Berger 1929, conserved name

Subfamily Cactoideae, tribe Trichocereeae. Plants shrubby, relatively small, branched or unbranched, erect or sprawling. Stems jointed, cylindrical. Ribs 10-18, low, narrow. Areoles small. Spines many, thin. Flowers borne nearthe stem tips, open at night, elongate funnelform, opening widely; pericarpels and floral tubes with wool, hairlike spines, and a few pointed scales. Fruits globose to inverted pear shaped, green with white pulp, thin walled, indehiscent, with scales, hairlike spines; floral remains persistent. Seeds obliquely ovoid, flat black, with low warts and wavy depressions. Distribution: western and southeastern Brazil.

Arthrocereus glaziovii (K. Schumann) N. P. Taylor 8c D. C. Zappi1991

Cereus glaziovii K. Schumann 1890, Leocereus glaziovii (K. Schumann) Britton & Rose 1920, Trichocereusglaziovii (K. Schumann) Werdermann 1933

Cereus damazioi K. Schumann 1903, not validly published; Arthrocereus damazioi (K. Schumann) P. V. Heath 1992, not validly published Trichocereus campos-portoi Werdermann 1933, Arthrocereus cam-

pos-portoi (Werdermann) Backeberg 1935 Arthrocereus itabiriticola P. J. Braun 1986

Plants erect with somewhat spreading branches. Stems 1.5-2 cm (0.6-0.8 in) in diameter. Ribs 12, low. Spines 20-30, awl shaped, brownish to ashy gray, 1.5-2.5 cm (0.6-1 in) long. Flowers slightly curved, white, to 6 cm (2.4 in) long. Fruits oblong, to 2 cm (0.8 in) long. Distribution: Minas Gerais, Brazil.

Arthrocereus melanurus (K. Schumann) Diers, P. J. Braun & Esteves 1987

Cereus melanurus K. Schumann 1890, Leocereus melanurus (K. Schumann) Britton & Rose 1920 Arthrocereus mello-barretoi Backeberg & Voll 1949, A. melanurus subsp. mello-barretoi (Backeberg & Voll) P. J. Braun & Esteves 1995 Arthrocereus odorus F. Ritter 1979, A. melanurus subsp. odorus

(F. Ritter) N. P. Taylor & Zappi 1997 Arthrocereus melanurus var. estevesii Diers & P. J. Braun 1988, A. melanurus subsp. estevesii (Diers & P. J. Braun) P. J. Braun & Esteves 1995

Arthrocereus melanurus subsp. magnus N. P. Taylor & Zappi 1997

Arthrocereus glaziovii, photograph by Gordon Rowley

Arthrocereus melanurus subsp. melanurus, photograph by Nigel Taylor

120 Arthrocereus melanurus

Plants branching basally with several stems to 1 m (3.3 ft) or more long. Stems short jointed, 10-40 cm (3.9-16 in) long, 2.5-3.5 cm (1-1.4 in) in diameter. Ribs 9-19, low, 2-3 mm high. Spines many, unequal, golden yellow to white. Upper radial and central spines as many as 15, brown, stout. Lower radial spines about 20, bristle-like, 5-8 mm (0.2-0.3 in) long. Flowers yellow to white, to 6 cm (2.4 in) long. Distribution: Minas Gerais, Brazil.

Three subspecies of Arthrocereus melanurus are recognized. Subspecies melanurushas 12-16 ribs and yellow flowers; it is the most widespread of the subspecies. Subspecies odorus has 9-12 ribs and white flowers; it occurs in Serra de Cipö. Subspecies magnus is larger and has 12-19 ribs; it occurs in Parque Estadual do Ibitipoca.

Continue reading here: Arthrocereus rondonianus Backeberg Voll 1935

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