Melocactus is one of several cephalium-bearing cacti, popular among hobbyists. For several reasons Melocactus is among the most fascinating globose cacti. I vividly recall seeing Melocactus for the first time when I was doing fieldwork in southern Ecuador. I also remember encountering spectacular specimens of Melocactus on Buck Island in the U.S. Virgin Islands. Those cacti that produce cephalia (Chapter 1, under Flowers) demonstrate two distinct growth phases. The first or juvenile phase of growth is nonreproductive, and the plants look like normal globose cacti. The second or adult phase results in a radical change in appearance through the production of the cephalium, which is a mass of areoles that produce the reproductive structures. The cephalia grow slowly and persist for years, producing flowers and fruits each season. In some cases the cephalia of Melocactus may reach nearly 1 m (3.3 ft) in height. Interestingly, many species of Melocactus cannot be transplanted from the wild after they have reached the adult stage.

Melocactus was probably among the first cacti observed by Europeans when they arrived in the New World late in the fifteenth century, and they were found in English collections before the end of the sixteenth century. They were first referred to as Echinomelocactus, which Joseph Pitton de Tourne-fort shortened to Melocactus in the early eighteenth century, the name derived from the Greek melon, apple, thus apple cactus. A Melocactus was among the 22 species of cacti described by Carl Linnaeus in Species Plantarum of 1753, which he named Cactus melocactus. In post-Linnaean times, Heinrich Link and Christoph Otto formally described the genus Melocactus in 1827, including four species, only one of which, M. macracanthos, is presently accepted, the others being mixtures or synonyms. Their M. communis, for example, includes material of M. intortus, M. curvispinus, and M. caroli-linnaei, the latter named by Nigel Taylor (1991a) to include Linnaeus's C. melocactus, the conserved type of the genus; "Melocactus melocactus" is not a permissible name botanically.

The first major study of Melocactus was published by Friedrich Miquel in 1840 with 34 species. Subsequent studies have shown that only 6 of those can be accepted, however, the others being synonyms or of questionable status. Nathaniel Britton and Joseph Rose (1919-1923,3:220), following rules of strict priority, returned to the Linnaean name Cactus for the genus. Over the years a large number of species have been proposed for Melocactus, in part a reflection of the great variability of populations. Thus there are numerous synonyms for the 33 species (and two naturally occurring hybrids) de

Matucana weberbaueri, photograph by Urs Eggli

scribed here; the monograph of Melocactus in Central and South America by Nigel Taylor (1991a) has clarified the taxonomy of the genus. All of the species flower during the day, the flowers usually opening mid- to late afternoon and closing at dusk. Pollination is primarily by hummingbirds, though insects may also be involved in some species.

Melocactus Link & Otto 1827, conserved name Cactus in the sense of Britton & Rose 1922, not Linnaeus 1753 (see Mammillaria)

Subfamily Cactoideae, tribe Cereeae. Plants solitary, depressed globose to cylindrical, usually less than 1 m (3.3 ft) high, without indeterminate growth. Ribs 8-27, vertical. Tubercles absent. Areoles small to large. Spines 3-21 or more, well developed, poorly differentiated as centrals and radials, sometimes hooked in young plants. Flowering portion a terminal cephalium bearing wool and bristles. Flowers short-lived, small, tubular, red to pink, naked. Fruits short to long club shaped, juicy, naked except for floral remains, white, pink, magenta, or reddish. Seeds globose to ovoid, black. Distribution: occurring widely in the western hemisphere from western Mexico south through Central America to Ecuador to southern Peru, east through the Amazon to eastern Brazil and Venezuela, Into the Caribbean.

Melocactus Xalbicephalus Burning & Brederoo 1973

Melocactus xalbicephalus is a naturally occurring hybrid, M. ernestiixM. glaucescens (Taylor 1991a). Distribution: Brazil.

Melocactus atldinus R. Gruber ex N. P. Taylor 1991

Plants depressed globose to elongate pyramidal, dark green to yellowish green to yellow, 8-25 cm (3.1-9.8 in) high, 10.5— 30 cm (4.1-12 in) in diameter. Ribs 10-15, acute. Areoles sunken into the ribs. Spines dark brown, becoming gray or reddish brown. Central spines 1-6, more or less straight, erect, 8-16 mm (0.3-0.6 in) long. Radial spines 7-15, similar to the centrals. Cephalia to 15 cm (5.9 in) high, 4.5-9 cm (1.8-3.5 in) in diameter, with dark rusty bristles and wool. Flowers open in the morning and close midafternoon, ex-serted above the cephalium, pale pink, 23-30 mm (0.9-1.2 in) long, 9-11 mm (0.4 in) in diameter. Fruits red at tips, paler below, 15-22 mm (0.6-0.9 in) long. Distribution: Andes of Colombia and western Venezuela at elevations of 15002200 m (4900-7200 ft).

Melocactus azureus Buining & Brederoo 1971


Melocactus ferreophilus Buining & Brederoo 1973, M. azureus subsp.

ferreophilus (Buining & Brederoo) N. P. Taylor 1991 Melocactus kralnzianus Buining & Brederoo 1975

Plants subglobose to cylindrical, dark to gray-green, sometimes glaucous, 13-45 cm (5.1-18 in) high, 14-19 cm (5.57.5 in) in diameter. Ribs 9-10, triangular in cross section. Spines black to reddish, overlaid with gray, some hooked in seedlings. Central spines 1-4, slighdy curved to straight. Radial spines 7-11. Cephalia to 12 cm (4.7 in) high, 7-9 cm (2.8-3.5 in) in diameter, with reddish bristles and brown or white wool. Flowers pinkish magenta, 19-23 mm (0.7-0.9 in) long, 8-11.5 mm (0.3-0.5 in) in diameter. Fruits white or sometimes pale pink, to 17 mm (0.7 in) long. Distribution: limestone in Bahia, Brazil, at elevations of450-800 m (15002600 ft).

Two subspecies of Melocactus azureus are recognized. Subspecies azureus has glaucous stems, especially when young, and bristles are usually not exserted above the tops of the cephalia but brown tufts of wool are present; it occurs at moderate elevations in northern central Bahia. Subspecies ferreophilus has stems that are never glaucous, and cephalia have bristles that are well exserted and lack brown wool; it occurs at elevations to 800 m (2600 ft) in central Bahia.

Melocactus bahiensis (Britton & Rose) Lutzelburg 1923 Cactus bahiensis Britton & Rose 1922, Melocactus oreas subsp. bahiensis (Britton & Rose) Rizzini 1982, M. oreas var. bahiensis (Britton & Rose) Rizzini 1983 Melocactus amethystinus Buining & Brederoo 1972, M. bahiensis subsp.amef/ijsfiwMs(Buining& Brederoo) N. P.Taylor 1991 Melocactusbrederooianus Buining 1972, M. inconcinnus var. bredero-

oianus (Buining) F. Ritter 1979 Melocactus grisoleoviridis Buining & Brederoo 1974

Melocactus azureus subsp. ferreophilus

Melocactus Inconcinnus

Melocactus azureus subsp. ferreophilus

458 Melocactus bahiensis

Melocactus lensselinkianus Buining & Brederoo 1974 Melocactus acispinosus Buining & Brederoo 1975 Melocactus inconcinnus Buining & Brederoo 1975 Melocactus ammotrophus Buining Brederoo & Bercht 1984 Melocactus glauxianus Brederoo & Bercht 1984

Plants globose, depressed globose, or pyramidal, pale to dark green, 9.5-21 cm (3.7-8.3 in) high, 11-21 cm (4.3-8.3 in) in diameter. Ribs 8-14, very low, variable in shape. Spines brown, reddish, or yellow, overlaid with gray, some curved or hooked in young plants. Central spines 1-4, mostly straight, 17-50 mm (0.7-2 in) long. Radial spines 7-12, mostly straight, to 60 mm (2.4 in) long. Cephalia usually small, to 5 cm (2 in) high, 6.5-8.5 cm (2.6-3.3 in) in diameter. Flowers pinkish magenta, 20-23 mm (0.8-0.9 in) long, 10-12.5 mm (0.4-0.5 in) in diameter. Fruits reddish to magenta above, paler below. Distribution: eastern Brazil.

Two subspecies of Melocactus bahiensis are recognized. Subspecies bahiensis is variable and has been further divided into forms; its stems have acute or rounded ribs, and it is found in the more northern part of eastern Brazil. Subspecies amethystinus has acute ribs that are triangular in cross section, and it is found farther south in the southern edge of Bahia and northern Minas Gerais.

Melocactus bellavistensis Rauh & Backeberg 1957 Melocactus onychacanthus Ritter 1966, M. bellavistensis subsp. ony-chacanthus (Ritter) N. P. Taylor 1991

Plants depressed globose to somewhat elongate and conical, shiny dark green, 6-25 cm (2.4-9.8 in) high, 8-25 cm (3.1-

Melocactus bahiensis subsp. bahiensis

9.8 in) in diameter. Ribs 9-18, sharply acute, with straight sinuses. Areoles sunken into notches in the ribs. Spines whitish to reddish yellow, with gray coating, usually curved downward, variable in stoutness. Central spines absent or 1-3, located in the upper parts of the areoles, sometimes inconspicuous, 1-17 mm (to 0.7 in) long. Radial spines 6-12, lower ones longest, to 25 mm (1 in), upper ones 1-8 mm (to 0.3 in) long. Cephalia to 15 cm (5.9 in) high, 6-10 cm (2.4-3.9 in) in diameter, with exserted reddish bristles and creamy white wool. Flowers open in mid- to late afternoon, deep pink, 18-26 mm (0.7-1 in) long, 5-10 mm (0.2-0.4 in) in diameter. Fruits red, 15-29 mm (0.6-1.1 in) long. Distribution: southern Ecuador and northern Peru.

Two subspecies of Melocactus bellavistensis are recognized. Subspecies bellavistensis has stems with 12-18 ribs, and central spines are absent or inconspicuous; it occurs in southern Ecuador and northern Peru. Subspecies onychacanthus, the more southerly subspecies, has stems with 9-12 ribs, and 0-3 central spines; it occurs only in northern Peru.

Melocactus broadwayi (Britton & Rose) A. Berger 1926 Cactus broadwayi Britton & Rose 1922

Plants globose to short cylindrical, yellowish green, 10-20 cm (3.9-7.9 in) high and in diameter. Ribs 14-18, low, rounded, acutely separated. Areoles small, depressed. Spines brown or horn colored, with brownish tips. Central spine usually one, sometimes 2-3, stout. Radial spines 8-10, curved inward, 10-15 mm (0.4-0.6 in) long. Cephalia 2-3 cm (0.81.2 in) high, 6-7 cm (2.4-2.8 in) broad basally, with soft brown bristles and white wool. Flowers small, purplish. Fruits club shaped, purple, to 25 mm (1 in) long. Distribution: Lesser Antilles and Tobago.

Melocactus bellavistensis subsp. bellavistensis
Melocactus Bellavistensis

Melocactus caroli-linnaei N. P. Taylor 1991 Cactus melocactus Linnaeus 1753

Plants cylindrical, to 1 m (3.3 ft) high, green. Ribs 10-15. Spines 10-12 or sometimes more, stout, yellowish to brownish, 3-5 cm (1.2-2 in) long. Cephalia with very dense, long-exserted, stout bristles that obscure the wool beneath except at the tip. Flowers narrowly cylindrical, red, to 40 mm (1.6 in) long. Fruits club shaped, red, to 50 mm (2 in) long. Distribution: Jamaica.

Melocactus concinnus Buining & Brederoo 1972 ?Melocactus pruinosus Werdermann 1934 Melocactus axlniphorus Buining & Brederoo 1976 Melocactus robustispinus Buining, Brederoo & J. Theunissen 1977, M. zehntneri subsp. robustispinus (Buining etal.) P. J. Braun 1988

Plants depressed globose, gray-green and glaucous, 8-13 cm (3.1-5.1 in) high, 11-16 cm (4.3-6.3 in) in diameter. Ribs 812, often laterally creased. Spines red to black, later yellowish and overlaid with gray except at the tips. Central spine one, upcurved, 10-19 mm (0.4-0.7 in) long. Radial spines 6-8, recurved, sometimes hooked at the tip, 15-26 mm (0.6-1 in) long. Cephalia to 5.5 cm (2.2 in) high, 4-9 cm (1.6-3.5 in) in diameter, with fine, dense, pale pinkish red bristles and cream-colored wool. Flowers barely to well exserted from the cephalia, deep pink, 20-23 mm (0.8-0.9 in) long, 6-12 mm (0.2-0.5 in) in diameter. Fruits pale lilac-pink to pink, 13-22 mm (0.5-0.9 in) long. Distribution: central Bahia to northern central Minas Gerais, Brazil.

Melocactus conoideus Buining & Brederoo 1973 CONE-LIKETURK'S-HEAD CACTUS

Plants strongly depressed globose to hemispheric, to 10 cm (3.9 in) high and 17 cm (6.7 in) in diameter. Ribs 11-14, very low and rounded. Spines dark brown, overlaid with gray, some curved or hooked in seedlings. Central spine one, 2022 mm (0.8-0.9 in) long. Radial spines 8-11, straight to slightly curved, to 35 mm (1.4 in) long. Cephalia to 4 cm (1.6 in) high and 7.5 cm (3 in) in diameter, with dark red bristles and abundant white wool. Flowers lilac-magenta, to 22 mm (0.9 in) long and 10 mm (0.4 in) in diameter, pinkish magenta. Fruits to 18 mm (0.7 in) long. Distribution: southeastern Bahia, Brazil. Melocactus conoideus is severely threatened by habitat destruction and is listed in Appendix I of cites.

Continue reading here: Melocactus curvispinus Pfeiffer 1837

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