Stephanocereus

Stephanocereus (type, Cereus leucostele = S. leucostele) was described by Alwin Berger in 1926. Curt Backeberg (19581962,4:2549), Pierre Braun (1988), and others accepted it as a genus with a single species. Earlier, however, Nathaniel Britton and Joseph Rose (1919-1923, 2: 60) had noted that another unusual cactus probably is related to C. leucostele, a plant subsequently described as C. luetzelburgii by Friedrich Vaupel. Nigel Taylor and Daniela Zappi (1989) later observed the same similarity. Taylor suggested to the International Cactaceae Systematics Group that this latter species be placed in a separate genus, Lagenopsis. Urs Eggli then observed that juvenile features of C. luetzelburgii are much like those of Stephanocereus leucostele. Consequently, the group decided to include S. luetzelburgii in Stephanocereus as the second of two species. Taylor and Eggli (1991), however, believe it distinct enough to merit placement its own subgenus.

The name Stephanocereus is derived from the Greek stephanos, crown, thus crowned cereus, referring to the crownlike cephalia on the stem tips. Stephanocereus appears most sim ilar to Pilosocereus but differs in having the single or rarely branched stem completely covered by dense white hairs and spines. The fertile zones are terminal cephalia, but vegetative growth commences again following the flowering season, thus creating ringlike structures. Sometimes the cephalia remain more or less apical. Flowers are often borne in clusters in the cephalia and are very large, white, and open at night in summer. The large fruits are blue.

Stephanocereus A. Berger 1926 Coieocephalocereus subg. Lagenopsis Buxbaum 1972

Subfamily Cactoideae, tribe Cereeae. Plants unbranched or occasionally sprouting basally, sometimes treelike, 1-5 m (3.3-16 ft) high. Stems globose or ovoid at first, then elongate to columnar or bottle shaped with thin necks. Ribs 12-20, low. Areoles with abundant white wool obscuring the stem. Central spines 1-4, stout, white to golden,

3-4 cm (1.2-1.6 in) long. Radial spines 15-20, yellow to white, 0.5-1.5 cm (0.2-0.6 in) long. Cephalia apical or ringlike and alternating with vegetative growth, with dense bristles, white wool, and hairs. Flowers tubularto funnelform, white to sometimes slightly pink, 5-10 cm (2-3.9 In) long; pericarpels and floral tubes with a few scattered small scales, areoles naked or with a small amount of white wool; perianth parts short, spreading. Fruits ovoid to ellipsoidal, blue to purplish green, naked, indehiscent; floral remains persistent, becoming black. Seeds large, ovoid to pear shaped, flat black, with tubercles. Distribution: Bahia, Brazil.

Taylor and Eggli (1991) recognized two subgenera of Stephanocereus: Stephanocereus for S. leucostele, and Lagenopsis for S. luetzelburgii.

Stephanocereus leucostele (Gurke) A. Berger 1926 Cereus leucostele Gurke 1908, Cephalocereus leucostele (Gurke) Britton & Rose 1920, Pilocereus leucostele (Gurke) Werdermann 1933

Plants mostly single, columnar, seldom branched, 2-5 m (6.6-16 ft) high. Stems with unequal segments, bluish green,

4-8 cm (1.6-3.1 in) in diameter. Ribs 13-18. Central spines 1-2, stiff, white to golden yellow, 3-4 cm (1.2-1.6 in) long.

Radial spines as many as 20, white, 0.5-1.5 cm (0.2-0.6 in) long. Cephalia ringlike, alternating with vegetative growth, densely woolly and hairy. Flowers sometimes borne from older cephalia as well as terminal ones, tubular to bell shaped, white, 6-7 cm (2.4-2.8 in) long. Fruits oblong, green, becoming blue, to 5 cm (2 in) long. Distribution: southern Bahia, Brazil.

Continue reading here: Stephanocereus luetzelburgii Vaupel n p Taylor Eggli

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