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The genus Melocactus has c.35 species distributed in Central and South America, the centre of diversity of the genus being the Brazilian state of Bahia, where 14 species occur. Here 11 are endemic, 5 of which are classified as Critically Endangered. In this work chromosome counts are recorded for 11 species: Melocactus bahiensis (subsp. amethystinus), M. conoideus, M. ernestii (subsp. ernestii, subsp. ernestii f. erythracanthus and subsp. ernestii f. azulensis), M. oreas (subsp. cremnophilus and subsp. oreas), M. concinnus, M. glaucescens, M. salvadorensis, M. violaceus (subsp. margaritaceus), M. zehntneri, M. xalbicephalus (a naturally occurring hybrid between M. ernestii subsp. ernestii and M. glaucescens) and M. paucispinus. M. violaceus subsp. margaritaceus presented 2n = 22, M. ernestii and M. zehntneri both had cytotypes with 2n = 22 and 2n = 44, and the remaining species had 2n = 44. The interspecific hybridization observed in the genus is discussed in relation to its reproductive biology and cytogenetic data.
This work describes the in vitro propagation of Turbinicarpus laui, a Mexican cactus considered as threatened with extinction. In vitro cultures were initiated using seeds. Five shoots per explant of T. laui were obtained on MS medium with 2.2 μM benzyladenine and two shoots on medium with 4.4 μM benzyladenine (P < 0.05) at 40 days. Quality of shoot was recorded as percentage of callus and hyperhydricity. The presence of callus was similar in both media at 20 days, but a reduction was observed at 40 days. A higher number of shoots with low hyperhydricity was obtained on medium with 4.4 μM benzyladenine. The development of shoots (measured as increase on epicotyl length, and fresh and dry weight after 6 weeks) was similar in both media. A continuous increase (15 to 20%) of new shoots was observed after subcultures and in about 1 year 1,200 well defined shoots of T. laui were obtained. Rooting of T. laui shoots was observed on media MS containing 1% polyethyleneglycol and 1% activated charcoal and the survival of the plants to soil was 80%. The first flowering was observed after 2 years in greenhouse conditions.
A new subspecies of Tacinga inamoena, T. inamoena subsp. subcylindrica M. Machado & N. P. Taylor, is described. The new subspecies differs from the typical subspecies in its erect habit, by its oblong stem-segments and by being smaller in all its parts.
Aloe camperi Schweinfurth is native to Eritrea and Ethiopia in East Tropical Africa. It is widely cultivated in southern Africa and has become naturalised on the lower slopes of Table Mountain, Cape Town.
Kalanchoe paniculata Harv. is one of the most widespread species of the genus in southern Africa. In this paper the occurrence of K. paniculata in the savanna and grassland regions of the country is illustrated, a new locality is reported and the ethnomedicinal uses of the species are described.
A catalogue of the living collections of Liverpool Botanic Garden, founded in 1802, was published in 1808. The Garden's herbarium was transferred to Liverpool Museum in 1909, and has now been documented on a computer database. A short history of the Garden is given along with an account of the succulent plants that were cultivated there during its early years (1802–1817).
The genus Cipocereus belongs to the subfamily Cactoideae, tribe Cereeae, and includes columnar or semi-erect species, endemic of the Serra do Espinhaço of Minas Gerais, Brazil. It is composed of five species: C. bradei, C. crassisepalus, C. laniflorus, C. minensis and C. pusilliflorus. It is considered to be one of the most primitive of the tribe, due to a vascular cylinder composed of secondary xylem with heavy lignification, among other morphological characters. The aim of the present work is to verify the occurrence of diagnostic and taxonomic features. Stem and branch samples of each species were cut at apical, medium and basal portions. Sections were stained with safranin and astrablue and mounted in synthetic resin. The species share the following characters: a uniseriate epidermis, with thick cuticle; an external cortex portion differentiated to have a hypodermis, with many layers of cells with very thick walls; a well developed palisade chlorenchyma containing mucilage cells. During the secondary vascular formation, sclereid precursors are present outside the secondary phloem, that give rise to sclereids in later stages. Primary rays are formed by the interfascicular cambium and secondary rays by the fascicular cambium, among the axial elements of xylem and phloem. The secondary phloem is composed of sieve tube elements with transverse simple sieve plate, companion cells, axial and radial parenchyma. The xylem is composed of vessel elements with simple perforation plates, septate libriform fibres, large and high rays, axial scanty paratracheal parenchyma. Species differences have been found in the hypodermis structure, the presence of crystals and mucilage cells.
Euphorbia filiflora is distributed on the high plateau of northern Namaqualand from Brakdam to north and north west of Steinkopf to Umdaus. A new variety is described, E. filiflora Marloth var. nana G.Williamson. This plant is a miniature and has a restricted distribution.
The new species Aloe bruynsii P.I.Forst. from near Manambaro in the Fort Dauphin district of south-eastern Madagascar is described and figured. It appears to be allied to A. acutissima H.Perr. that occurs in south-western Madagascar.
Distribution, abundance and condition of Aloe pillansii in Namibia were assessed. It was previously believed that the world population numbered fewer than 200 individuals, of which most occurred in South Africa. More than 1500 individuals were found in five populations. The largest population appears to be in a poor condition, possibly due to mining activities nearby. Low recruitment was observed in all populations. Possible reasons for this are discussed, and the situation in Namibia is contrasted with that in South Africa.
A review of the literature concerning Opuntia lagopus Schumann is presented and the nomenclature of this opuntioid species from the high Andes of southern Peru is clarified. A new combination, Austrocylindropuntia lagopus (Schumann) I.Crook, J.Arnold & M.Lowry is made for the taxon and the name fixed through designation of a neotype. The distribution of the species is extended and observations made on its interaction with its habitat.
Based on investigations in the field and in herbaria over several years, it is possible now to identify the species Trichodiadema intonsum. Confusions with T. bulbosum, T. concinnum, T. decorum, T. introrsum, and T. orientale are discussed, the species limits and their variations are described, synonyms are listed, a key is offered, and the accepted taxonomy is presented.
A detailed study of Lampranthus has shown that several of its species are more closely related to other taxa within the Aizoaceae than they are to Lampranthus. Here some of these anomalous species are transferred to the genera Esterhuysenia, Oscularia, Antimima, Erepsia and Ruschia. A new genus, Phiambolia Klak, is erected to accommodate a group of taxa which cannot be placed in any of the existing genera. The appropriate new combinations are made. In addition, the new species Phiambolia mentiens Klak, Brownanthus lignescens Klak, Acrodon deminutus Klak, Lampranthus procumbens Klak and Drosanthemum quadratum Klak are described.
C-value was applied as a new criterion to investigate the relationships within the genus Agave L. (Agavaceae). Samples representing nearly 40 taxa were investigated, augmented with data from the literature. Species of Agave have the same basic chromosome number, x = 30, but there are several polyploids. Their somatic nuclear DNA contents (2C), as measured by flow cytometry with propidium iodide falls in a narrow range around 8 pg for the diploids. A comparison is made with nuclear DNA amounts of other related genera. Hosta, with a chromosome complement identical to that of Agave, with 5 large and 25 small chromosomes in the haploid set, is at the base of the Agavaceae clade and has two to three times the amount of nuclear DNA of the other genera.
We review and discuss a number of DNA extraction protocols written for mucilaginous plants. Two relatively simple methods are presented here that have been used to reliably obtain molecular data from mucilaginous cacti. We propose that the methods presented here can achieve usable results with a minimum of time and expense.
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