Bradleya 31/2013 pages 142-149 Coleocephalocereus purpureus has a cephalium; Micrantho - cereus streckeri has a pseudocephalium (Cereeae, Cactoideae, Cactaceae) Root Gorelick Department of Biology, School of Mathematics & Statistics, and Institute of Interdisciplinary Studies Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 Canada. (email: [email protected]). Photographs by the author Summary : The putatively closely related cactus Introduction genera of Coleocephalocereus , Micranthocereus , Cactaceae (cacti) in the tribe Cactoideae have Cereus , Monvillea , and Stetsonia have a wide a wide range of reproductive anatomies ranging range in specialization of reproductive portions of from cephalia to pseudocephalia to forms where the shoot, from cephalium to pseudocephalium to reproductive and vegetative structures are indis - no specialization. After briefly summarizing the tinguishable (Buxbaum, 1964, 1975; Mauseth, shifting uses of the terms ‘cephalium’ and ‘pseudo - 2006). cephalium’, I provide gross morphological evi - For instance, Melocactus Link & Otto, Disco - dence that Coleocephalocereus purpureus has a cactus Pfeiffer, and Espostoa Britton & Rose have true cephalium that is formed of a continuous true cephalia in which the flowering parts are not swath of bristles and hairs, with its underlying photosynthetic because every epidermal cell con - thick cortex of parenchyma replaced by a narrow tains a modified leaf that is a hair, bristle, or layer of cork. By contrast, Micranthocereus streck - spine, with no stomata amongst the epidermal eri has a pseudocephalium composed of nothing cells (Mauseth, 2006). Furthermore, there are more than larger hairier areoles in which the un - changes to the internal anatomy of cephalia, derlying epidermis is still photosynthetic and the where the underlying cortex is not a wide swath of underlying cortex is still a thick layer of highly succulent parenchyma, but instead a thin parenchyma without any noticeable cork. layer of cork. By contrast, pseudocephalia are composed of Zusammenfassung : Die vermuteterweise nahe relatively normal areoles that simply grew more miteinander verwandten Kakteengattungen hairs or bristles. The areoles themselves may also Coleocephalocereus , Micranthocereus , Cereus , be larger and closer to being confluent. The epi - Monvillea , und Stetsonia haben ein weites Spek - dermis of a pseudocephalium is still photosyn - trum an Spezialisierungen der reproduktiven thetic (chlorenchyma) with stomata, and the Sprossabschnitte, variierend von Cephalien zu underlying cortex is unchanged, with a thick layer Pseudocephalien, und ohne Spezialisierung. Nach of succulent parenchyma (Mauseth, 2006). As einer kurzen Zusammenfassung der im Laufe der with true cephalia, pseudocephalia usually grow Zeit unterschiedlichen Verwendungen der Be - directly from the shoot apical meristem, as in Pi - griffe `Cephalium' und `Pseudocephalium' stelle losocereus Byles & G.D. Rowley and Cephalocleis - ich allgemeine morphologische Evendenzen vor, tocactus F. Ritter (cf. Buxbaum, 1964). Many cacti dass Coleocephalocereus purpureus ein echtes with pseudocephalia are also like those with Cephalium hat, das aus einem kontinuierlichen cephalia in that flowers are only produced from Streifen aus Borsten und Haaren besteht, dessen specialized areoles, i.e. those with long copious darunterliegender dicker parenchymatischer Cor - hairs and bristles, although a few species such as tex durch eine dünne Korkschicht ersetzt wird. Im Arrojadoa hofackeriana (P.J. & Esteves) P.J. Gegensatz dazu hat Micranthocereus streckeri ein Braun & Esteves [synonyms: Micranthocereus ho - Pseudocephalium, das lediglich aus grösseren und fackeriana (P.J. Braun & Esteves) Machado and stärker behaarten Areolen besteht, bei dem die Arrojadoa multiflora F. Ritter subsp. hofackeri - darunterliegende Epidermis weiterhin photosyn - ana P.J. Braun & Esteves] can produce flowers thetisch bleibt, und bei dem der darunterliegende from both the pseudocephalium and more juve - Cortex weiterhin aus einer dicken Parenchym - nile-looking (non-wooly) areoles (Braun & Esteves schicht besteht, ohne auffällige Korkbildung. Periera, 2007). 142 Bradleya 31/2013 Figure 1. Pilosocereus gounellei subsp. zehntneri , Figure 2. Espostoa melanostele , radial section of with pseudocephalia arising from shoot apical young cephalium, with flower bud. meristems. Figure 3. Espostoa melanostele , cross section (of Figure 4. Coleocephalocereus purpureus , in habi - excised section from Figure 2) with cephalium on tat. left. Figure 5. Coleocephalocereus purpureus , shoot Figure 6. Coleocephalocereus purpureus , cross that was sectioned in Figures 6-8. section. Bradleya 31/2013 143 My modest goal was to determine whether ium (e.g. Zavala-Hurtado et al., 1998, Valverde et Coleocephalocereus purpureus (Buining & al ., 2007). Similarly, Gürke (1908) used the term Brederoo) F. Ritter and Micranthocereus streckeri ‘cephalium’ for all specialized wooly floriferous Van Heek & Van Creik. have a cephalium or in - portions of cactus shoots, when speaking of stead a pseudocephalium. Both species are in the Facheiroa ulei (Gürke) Werderm. [as Cephalo - tribe Cereeae (Hernández-Hernández et al ., 2011), cereus ulei Gürke] and Micranthocereus pur - which contains plants with cephalia ( Melocactus , pureus (Gürke) F. Ritter [as Cephalocereus Discocactus , Arrojadoa Britton & Rose), plants purpureus Gürke]. with pseudocephalia (several Pilosocereus Britton & Rose (1919-1923) confined use of the species), plants with neither a cephalium nor term ‘cephalium’ to Melocactus and Discocactus , pseudocephalium ( Cereus Miller; with the possi - calling all other specialized reproductive struc - ble exception of the enigmatic C. mortensenii tures ‘pseudocephalia’. A “cephalium [is] com - (Croizat) D.R. Hunt & N.P. Taylor), and a few posed of a central woody core surrounded by a plants that are ambiguous (e.g. Stetsonia coryne dense mass of long wool, bristles or both” (Britton (Salm-Dyck) Britton & Rose, which is like & Rose, 1922: 216). “Flowering areoles develop an Carnegiea gigantea Britton & Rose and Brown - abundance of wool which confluently forms a ingia candelaris (Meyen) Britton & Rose in only dense mass called a pseudocephalium either at flowering from relatively spineless areoles). the top or on one side near the top” (Britton & Surprisingly, there has been almost no pub - Rose, 1920: 25). Britton & Rose (1920) referred to lished work on the morphology of cephalia and all known species of Coleocephalocereus Backe - pseudocephalia. These structures have been sec - berg and Micranthocereus Backeberg as Cephalo - tioned and the results published on only a few cereus , which they claimed had pseudocephalia. cacti, such as Melocactus spp., Espostoa spp., Many subsequent authors followed Britton & Cephalocereus senilis Pfeiffer, C. columna-trajani Rose’s tradition of reserving the term ‘cephalium’ (Karw.) K. Schum., and Pachycereus militaris exclusively for Melocactus and Discocactus , e.g. (Audot) D.R. Hunt [synonym: Backebergia mili - Gibson & Nobel (1986). Anderson (2001: 697) even taris (Audot) Sánchez-Mej.] (Mauseth, 1999, 2006; more explicitly concurred with Britton & Rose by Mauseth et al ., 2005; Vázquez-Sánchez et al ., defining a pseudocephalium as “a lateral cephal - 2005, 2007), but apparently not on other taxa, ium”. such as the two species investigated herein. Backeberg (1934-1938) applied the term ‘cephalium’ to the following taxa (I have listed A short history of the terms cephalium and modern names, not Backeberg’s): Melocactus , Dis - pseudocephalium cocactus , Arrojadoa , Stephanocereus leucostele , The above distinction between cephalia and Facheiroa Britton & Rose, Espostoa , Espostoopsis pseudocephalia is modern, with older literature Buxbaum, Coleocephalocereus , Cephalocereus , and even some current literature giving different and Neobuxbaumia macrocephala (F.A.C. Weber definitions of these two terms. I therefore give a ex K. Schum.) E.Y. Dawson. Backeberg only used brief history of the use of these terms. the term ‘pseudocephalium’ for Micranthocereus Hooker used the term ‘cephalium’ in several of and Pilosocereus Byles & G.D. Rowley. Note, how - his Latin diagnoses in Curtis’s Botanical Maga - ever, that he claimed that Cephalocereus pur - zine , but never defined the term and seemed to pureus Gürke and Cephalocereus macrocephalus use the term somewhat indiscriminately, for ex - F.A.C. Weber ex K. Schum. have cephalia, even ample, from a panoply of plants that we now usu - though I would label these plants Micrantho - ally call Melocactus intortus (Mill.) Urb. (1831, cereus purpureus (Gürke) F. Ritter and Vol. 58, Tab 3090), Parodia ottonis (Lehm.) N.P. Neobuxbaumia macrocephala , respectively, and Taylor (1831, Vol. 58, Tab 3107), Echinopsis say that they probably have pseudocephalia, as I eyriesii Turpin (1835, Vol. 62, Tab 3411), Gymno - believe do all Micranthocereus and Cephalocereus calycium gibbosum (Haw.) Pfeiffer ex. Mittler species that have specialized wooly flowering are - (1837, Vol. 64, Tab 3561) and Echinocereus oles. Backeberg (1934-1938) also noted whether rigidissimus Rose (1845, Vol. 71, Tab 4190). some lateral cephalia were channeled or sunken The earliest definition I could find of a ‘cephal - in a cleft, as in Coleocephalocereus fluminensis ium’ is “the floriferous region of the plant is dif - (Miquel) Backeberg, Espostoa lanata (Kunth) ferentiated from the rest” in Berger’s (1907: 61) Britton