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 CACTUS & Co. 2 (8) 2004  CACTUS & Co. 2 (8) 2004 
 +
 +{{:​backebergia:​backebergia.pdf|Version pdf }}
  
 ===== INTRODUCTION ===== ===== INTRODUCTION =====
Ligne 1033: Ligne 1035:
 ies, carried out also on a genetic basis, and extended to ies, carried out also on a genetic basis, and extended to
 the whole distribution area. the whole distribution area.
 +
 +====== ​ Localities of B. militaris ======
 +
 +Colima:​Cited with no specific data (H. Bravo-Hollis,​ 1978)
 +- not confirmed. Jalisco: Pico de Colima (Lemaire, 1847,
 +perhaps today’s Nevado de Colima), probably referred to
 +the nearby location of Jilotlán de los Dolores (Chazaro,
 +1995 and Jean-Marc Chalet, pers. comm.) Michoacán:
 +Type Locality: ​ Basin of the Tepalcatepec river - near
 +Apatzingán and, more to the south-east, the ‘Infiernillo’
 +dam (H. Bravo-Hollis,​ 1953). Pinzandaran,​ La Ceibita,
 +Cinco de Mayo (Jean-Marc Chalet, 2003). ​ Guerrero:
 +Basin of the Balsas River – several locations (not specified,
 +Anderson 1994), perhaps relative to Ciudad Altamirano
 +(H. Bravo-Hollis,​ 1953); Petatlán (Sánchez-Mejorada cit. in
 +H. Bravo-Hollis,​ 1978) - not confirmed, probably a mistake
 +(it is outside the species’ area of distribution)
 +
 +====== Historique ======
 +
 +The many changes in status and synonymy, and nomenclatural mistakes regarding Backebergia place it among the first positions in the Guinness of taxonomical rebuses.
 +
 +1836/ Pilocereus militaris Hort.
 +1839 militaris = for the resemblance of the inflorescence to the hel-
 +met of English grenadiers,
 +quoted in Förster, C. - Handbuch der Cacteenkunde,​ p. 652,
 +(1886).
 +Year of the discovery of the species, by the explorer Joseph
 +Vandick from Antwerp, who collects some specimens and
 +sends them to the collector M. de Jonghe in Brussels. The
 +plants are observed by the French horticulturist M. Cels, who
 +gives them their first name.
 +1845 Cereus militaris Audot - in Revue Horticole 2: 307
 +The French horticulturist Audot writes the first valid descrip-
 +tion of the species.
 +1845 Pilocereus niger Neumann - in Revue Horticole II, 2: 289
 +In the same publication the botanist Neumann describes a new
 +cactus species seen at the Jardin des Plantes in Paris. They are
 +samples donated by the Mexican politician and naturalist
 +Melchor Ocampo, belonging to the same species discovered by
 +Vandick. ​
 +1847 Pilocereus chrysomallus Lemaire, in Flore des Serres et des
 +Jardins de l’Europe 3: 242
 +chrysomallus = with a yellow head
 +M. Galeotti’s herbarium is enriched with some cactus samples
 +coming from the locality “Pico de Colima” (perhaps today’s
 +Nevado de Colima in Jalisco). Lemaire doesn’t recognize the
 +same species described by Audot and Neumann and writes a
 +new description.
 +1849/ Pilocereus militaris Hort. ex Salm-Dyck, in Cact. Hort. Dyck.  ​
 +1850 ed. II. 40. Invalid name
 +1880 Cereus chrysomallus ​ (Lemaire) Hemsley, in  Biologia
 +Centrali-Americani,​ Botany 1: 541
 +Hemsley includes ​ Pilocereus chrysomallus in the genus
 +Cereus, creating a new combination of Lemaire’s name.
 +1894 Cephalocereus chrysomallus (Lemaire) Schumann, in  Engler
 +et Plantl, Pflanzenfam. 3 (6°), 182
 +Schumann recombines Pilocereus chrysomallus as Cephalocereus
 +chrysomallus and places ​ Pilocereus militaris ​ Hort., ​ Cereus
 +chrysomallus Hemsley and  Pilocereus chrysomallus as syn-
 +onyms. Pico de Colima becomes the type locality for the species.
 +1920 Pachycereus chrysomallus ​ Britton & Rose non Lemaire,
 +1847, in The Cactaceae, Washington DC
 +Britton & Rose reckon that Pilocereus fulviceps Weber (Cereus
 +fulviceps ​ sensu Berger) ​ from Puebla (Tehuacán) is the same
 +species described as Pilocereus chrysomallus by Lemaire and
 +coming from Pico de Colima. When they create the new genus
 +Pachycereus they include also  Pilocereus fulviceps ​ in it, but
 +with the wrong name “chrysomallus” belonging to the plant
 +described by Lemaire, and therefore they place in synonymy
 +Pilocereus chrysomallus ​ Lemaire, ​ Cereus chrysomallus
 +Hemsley, ​ Cephalocereus chrysomallus ​ Schumann, ​ Pilocereus
 +fulviceps Weber and Cereus fulviceps Berger. They include in
 +the list also  Cereus militaris ​ Audot and  Pilocereus militaris
 +Schumann as probable synonyms.
 +1942 Mitrocereus chrysomallus Backeberg - in Cact. J. DKG, 48: 77
 +Curt Backeberg reckons that the formation of the cephalium,
 +characteristic of the species from Tehuacán (Pilocereus fulvi-
 +ceps  Weber), is a character sufficient to separate it from
 +Pachycereus,​ and therefore he includes it in  Cephalocereus,​
 +subgenus Mitrocereus,​ of which it becomes the type species.
 +Also Backeberg’s work is based on Britton & Rose’s erroneous
 +description;​ he doesn’t bother to observe herbarium speci-
 +mens and uses the epithet Pilocereus chrysomallus. ​ At this
 +date Backeberg raises subgenus ​ Mitrocereus ​ to the rank of
 +genus and the type species becomes Mitrocereus chrysomal-
 +lus: Britton & Rose’s species from Tehuacán.
 +1953 Backebergia chrysomallus ​ (Lemaire) H. Bravo, in An. Inst.
 +Biol. Mex. 24:230 (1953)
 +Helia Bravo-Hollis rediscovers the species after almost 106 years
 +and decides to rename it on the basis of Lemaire’s description
 +of Pilocereus chrysomallus,​ clearing Britton & Rose’s mistake
 +and therefore creating a new monospecific genus.
 +1961 Mitrocereus militaris (Audot) H. Bravo ex Buxbaum, in Bot.
 +Stud. 12: 54
 +Buxbaum declares that the species ​ Pilocereus chrysomallus
 +Lem., on which Bravo’s description is based, is a nomen con-
 +fusum and renames the species according to the rules of
 +nomenclature,​ which impose the use of the last name consid-
 +ered valid.
 +1973 Backebergia militaris ​ (Audot) H. Bravo ex Sánchez-
 +Mejorada, in Cact. & Succ. J. US 155: 171
 +Sanchez-Mejorada points out that Buxbaum has wrongly
 +referred to the name of a genus attributed to another species.
 +However, he agrees with the need of abandoning the specific
 +name  chrysomallus. He adopts again the name  Backebergia
 +associating it with the specific name militaris.
 +1975 Cephalocereus militaris (Audot) H.E. Moore, in Baileya 19 (4): 166
 +Moore follows D. Hunt in widening the genus Cephalocereus,​
 +and includes in it  Backebergia militaris together with
 +Mitrocereus fulviceps.
 +1987 Pachycereus militaris (Audot) D. Hunt, in Bradleya 5: 93
 +David Hunt makes up for Britton & Rose’s mistake, recognizing
 +as valid the inclusion of the species in their genus Pachycereus
 +and Audot’s specific epithet. He does not offer any justification
 +for such a revision.
 +
 +====== WHERE DOES IT COME FROM? ======
 +
 +Among the species closest to  B. militaris there
 +could be  Pachycereus pecten-aboriginum. The
 +young seedlings of the two species are quite simi-
 +lar (Fig. 13 B. militaris, Fig. 14 P. pecten aborigi-
 +num): very large cotyledons, 7-8 ribs, numerous
 +white acicular spines.
 +Both  P. pecten-aboriginum (on the left) and  B.
 +militaris (on the right) would have originated from an ancestor with spiny fruits (A). In B. mili-
 +taris, the formation of the inflorescence occurred
 +thanks to the co-evolution with a lepidopteran
 +insect, through the stage of a pseudo-tiponche (B)
 +(similarly to what can be seen today in the species
 +Pachycereus schottii of Sonora), till it reached, due
 +to the greater and greater concentration of fertile
 +areoles at the apex of the stem (C), the stage of a
 +true tiponche.
 +The two evolutionary lines lead to opposite results
 +in the number and size of fruits and in the con-
 +centration of flowers along the stem.
 +
 +
 +====== CEPHALIUM VS. PSEUDOCEPHALIUM VS. TIPONCHE ======
 +
 +In many cacti there is evident dimorphism between
 +sterile areoles, producing only spines, bristles and tri-
 +chomes, and fertile areoles, that can also produce a
 +flower bud.
 +In many species of small globular cacti the fertile areoles
 +completely substitute the sterile ones when the plant
 +reaches reproductive maturity. They can be distinguished
 +by their stronger and more conspicuous spines
 +(Coryphantha) or for their spines transformed in bristles
 +amidst abundant wool (Discocactus). In these cases, in a
 +specimen reaching reproductive maturity all the areoles
 +of the apical portion are different from those of the basal
 +one, with little alterations in stem morphology. In other
 +cases, the production of fertile areoles occurs only during
 +a certain phase (flowering period) of plant growth, after
 +which sterile areoles are produced again. In this instance
 +there is a false cephalium, formed by these groups of fer-
 +tile areoles, that may be lateral (Cephalocleistocactus
 +sensu Ritter) or apical (Arrojadoa, Stephanocereus,​
 +Neodawsonia). ​
 +In other cases still, dimorphism does not refer only to the
 +areoles, but it also interests a portion of the stem, giving
 +rise to evident morphological changes. Two different
 +models may be distinguished:​ pseudo-cephalium and
 +cephalium.
 +The  pseudo-cephalium has evolved independently in
 +some genera belonging to the tribes Pachycereae
 +(Cephalocereus) and Cereae (Micranthocereus,​
 +Coleocephalocereus). It is the group of fertile, densely
 +pubescent areoles that develop preferentially along one
 +side of the stem of columnar cacti. There the cortex is fully
 +developed, and sometimes a thick periderm is produced,
 +which stiffens the epidermis and therefore inhibits photo-
 +synthesis. When present, the periderm is produced after the stem has fully developed, and fuses together all fer-
 +tile areoles.
 +The cephalium has evolved independently in some
 +genera belonging to the tribes Trichocereae
 +(Espostoa, Espostoopsis, ​ Facheiroa, Trixantho-
 +cereus) and Cereae (Melocactus). It is the group of
 +fertile, densely pubescent areoles that develop later-
 +ally on columnar species and on the apex of globu-
 +lar ones. It matures precociously (near the vegeta-
 +tive apex) and there the cortex soon stops thicken-
 +ing, so that growth is not congruous with the rest of
 +the stem (Mauseth, 1999). In the case of columnar
 +species the cephalium remains sunken in the stem,
 +while in the case of Melocactus, where it is apical, its
 +diameter is only a portion of that of the stem.
 +In comparison with the two cases described, the
 +inflorescence of  Backebergia is morphologically
 +similar to the cephalium of Melocactus. However, its
 +ontogenetic characters bring it closer to a pseudo-
 +cephalium. Indeed in this case too, the stem of the
 +rachis can reach its maximum development in diam-
 +eter, analogous to that of the stem, before the pro-
 +duction of periderm (see the paragraph on tiponche
 +structure).
 +This analogy notwithstanding,​ the present study
 +brings evidence to absolutely original morphologic
 +and functional factors (the phenomenon of ‘pro-
 +grammed’ detachment of the inflorescence,​ with all
 +that this implies), that lead me to consider the inflo-
 +rescence of  Backebergia as a highly sophisticated
 +structure, NOT homologous to cephalium nor to
 +pseudo-cephalium. So original, indeed, as to
 +deserve a distinct definition.
 +For this reason I have chosen the term ‘TIPONCHE’
 +(pron. Teepònche),​ coming from the vernacular
 +name with which the plants of B. militaris are com-
 +monly called in their distribution area.
 +
 +====== B. MILITARIS IN CULTIVATION ======
 +
 +After being rediscov-
 +ered by Helia Bravo-
 +Hollis, this plant has
 +attracted collectors, but
 +only at the beginning of
 +the ‘70s did the collection
 +and commerce of
 +tiponche cuttings start.
 +Probably, some expert col-
 +lector of botanical rarities
 +had noticed that a fallen
 +off branch with inflores-
 +cence could root and
 +grow normally.
 +It is reported that in
 +1979, nurseries in
 +Texas, close to the
 +Mexican border, sold
 +hundreds of cuttings
 +with naked roots, or still to root. These plants were spread
 +here and there throughout the world, but at costs too high
 +for most of the common collectors, so that they became
 +the attraction of the local merchant, who could show off
 +his jealously kept and strictly not-for-sale specimen.
 +After a while, those who had the ‘luck’ of buying these inter-
 +esting plants soon found out that they were extremely difficult to
 +keep alive: after producing a few flowers, the plants did not keep
 +on forming the lovely inflorescence,​ but they became etiolated,
 +or they grew new branches quite similar to those of any cereus.
 +However, in most cases they stopped growing and the inflores-
 +cence died, leaving only, as a sad memory, a collapsed mass of
 +blackened bristles.
 +In view of what I have written above, it is easy to imagine that
 +these cuttings could not live for long: the high request for organ-
 +ic matter caused an immediate crisis, and it was no use for them
 +to elongate, trying to change a flowering branch into a photo-
 +synthetic one.
 +The  Backebergia plant with no tiponche, instead, grows
 +without any particular problem. It can be treated as any colum-
 +nar species from the ‘hot’ tropics, such as  Pilosocereus,​ it enjoyes adequate fertilization and grows rapidly.
 +In order to flower, it needs a very tall greenhouse, where the
 +temperature must be high all around the year (young plants can
 +stand temperatures close to zero). The only known plant of this
 +species who has reached reproductive maturity in cultivation is
 +to be found in the botanical garden of La Habana, Cuba. Even
 +though the climatic conditions in Cuba are fine, the specimen is
 +kept in the greenhouse, probably to protect the cactus collection
 +from too much rain. This has certainly determined the success in
 +cultivation of this plant, known locally as the ‘Russian Soldier’, for
 +its tiponche. This is an interesting example, because it allows the
 +study of the life cycle of the plant in a location that is not subject
 +to the local climatic conditions.
  
 ===== ACKNOWLEDGEMENTS ===== ===== ACKNOWLEDGEMENTS =====