Plants with sunken growth never shed their leaves completely but keep their leaf tips level with the ground most of the time, being difficult to detect in habitat. In Aizoaceae, 73 species in the 12 genera Aloinopsis (1), Argyroderma (2), Conophytum (21), Dinteranthus (1), Fenestraria (1), Frithia (2), Gibbaeum (3), Lithops (36), Psammophora (1), Tanquana (2), Titanopsis (2), and Vanheerdea (1) possess this life form exclusively or predominantly; in Fenestraria (1), Frithia (2), and Lithops (36), only subterranean growth is known. Protection from predators and reduction of evaporation, supported by the development of mostly xeromorphic features in the outer epidermal wall, appear to be the main adaptive traits in all taxa, combined with the ability of the plants to inhabit small niches of soft soil in often stony terrain, making use of the lack of competition from bigger plants with more extensive root systems. Completely different strategies have been found, confirming that no single way of evolution for subterranean plants exists. In most genera, the sunken growth is found in few species only in marginal parts of the distribution area, but Lithops has spread over a very wide area with different climatic conditions, presenting all states of speciation and hence difficult to handle in the hierarchal taxonomic system. Conophytum, on the other hand, has evolved a number of species, too, but these are most often adapted to specific soils like quartz and seem to represent parallel evolutionary lines.

The genus Micranthocereus includes nine endemic Brazilian species distributed in the states of Bahia, Minas Gerais, Goiás and Tocantins. In the present study the floral biology of M. flaviflorus, M. streckeri and M. purpureus from “campo rupestre” vegetation of the Chapada Diamantina, Bahia, was investigated. Data on floral morphology and nectar production (concentration and volume) were collected throughout anthesis. Flowers of all species are tubular and present coloured perianth-segments. Nectar is accumulated within a nectar-chamber, located inside the floral tube. Flowers of M. flaviflorus and M. streckeri are predominantly nocturnal, opening in the night (at about 7 p.m.). Each flower lasts c.36 hours, with a concentration of sugar in the nectar between approximately 18–24%. Both species present floral features typical for ornithophily, and were pollinated by the hummingbird Chlorostilbon aureoventris, whose visits occurred in regular intervals and were characterized by territorialist behaviour. Species of bees and butterflies were also observed visiting flowers of M. flaviflorus and M. streckeri. M. streckeri was additionally visited by the hummingbird Phaethornis squalidus, mainly in the afternoon. Flowers of M. purpureus are nocturnal, and each flower lasts c.17 hours and present longer corollas with wider diameter than those of the other two species studied; sugar concentration in the nectar was about 21–22%. Three sphingid and one bat species were observed visiting flowers of M. purpureus, with a greater frequency of visits of the sphingids. Pollen viability was high (80–90%) and similar between the three species of Micranthocereus studied.

Wide-band tracheids (WBTs) were present in species with dimorphic and monomorphic wood. In all types of dimorphic wood in which WBTs were present, the phase that contains the WBTs is produced first. In seedlings of Cipocereus minensis the first phase consists of vessels and parenchyma in a matrix of wide-band tracheids and the second phase consists of a fibrous matrix with vessels and parenchyma (wide-band tracheid wood followed by fibrous wood). Adult plants of Discocactus placentiformis and Melocactus ernestii have monomorphic WBT wood which consists of parenchyma distributed in the form of small clusters between the vessels and wide-band tracheids. In all species examined a band-like secondary wall is present in the form of annular rings or a helix. We observed annularhelical thickening in D. placentiformis and M. ernestii or a double-helix in D. placentiformis.

Adenia goetzei is a plant with a decorative prominent caudex. An efficient micropropagation system based on axillary shoot formation and subsequent rooting was developed. By alternating culture on a medium with 5µM BAP (a modified Murashige & Skoog (1962) medium) and a medium without BAP (Krogstrup et al., 1988), a multiplication factor of 3.93 /- 1.16 (mean /- SD) was achieved every 6 weeks. Approximately 61 % of the micro-cuttings rooted following a 24 day 5µM IBA treatment and 80–85% of the plants were successfully transplanted to soil. The juvenile twining growth- and leaf form reverted to a form with adult characteristics after 1–2 growth periods in soil. Using this micropropagation protocol for A. goetzei, it has been possible to produce several hundred vigorous and true-to-type plants, except for irregularly shaped caudices in contrast to the regular ones seen in seedlings.

Description of two new species in the genus Aloe from Madagascar. The first, A. charlotteae Castillon, comes from the Andringitra massif, in the centre of the island; the second, A. mitsioana Castillon, has been found on a small island near Ambilobe in the north of Madagascar.

The anatomy of Blossfeldia liliputana was compared with that of Notocactus, Parodia, Frailea, and numerous dwarf cacti to investigate the DNA-based hypothesis that Blossfeldia may be basal within Cactoideae (Nyffeler, 2001). Cortical bundles are present in every member of Cactoideae ever investigated except for Blossfeldia. Lack of cortical bundles could represent an ancestral condition because they are also absent from Pereskia, Maihuenia, and all Opuntioideae as well as most vascular plants. If so, Cactoideae would have diverged early into two lineages, one of which gave rise to Blossfeldia, the other of which produced the rest of the Cactoideae after cortical bundles originated. Alternatively, lack of cortical bundles could represent a loss that occurred recently as dwarfism evolved in the Blossfeldia lineage, for example after the Blossfeldia lineage diverged from the Notocactus, Parodia, or Frailea lineage. However, none of the other dwarf cacti investigated here has lost their cortical bundles, so such loss in Blossfeldia would be unique within Cactaceae. The epidermis of Blossfeldia is ephemeral, converting to a cork cambium while only a few weeks old, a feature that also occurs in Pereskia and Maihuenia but almost no other cacti. Stomata and photosynthetic aerenchyma occur only at the base of areole pits, just as occurs in Maihuenia but no other known cactus. All these features are consistent with Blossfeldia being basal in Cactoideae, but do not disprove the alternative theory of its being a highly derived taxon instead.

This study describes a method to micropropagate Ariocarpus kotschoubeyanus, using coconut water and darkness conditions. The longitudinal explants from seedlings germinated in vitro were cultivated on Murashige and Skoog medium (MS) with 2 mg/l zeatin. The calli generated were transferred to medium containing 5 ml, 10 ml or 15 ml of coconut water per litre. After 84 days, five green shoots per callus were generated under photoperiod but 14 well defined shoots were produced in darkness. The shoots were cultivated on media with activated charcoal and polyethyleneglycol to reduce callus and hyperhydricity, respectively. To induce rooting the effect of the auxins indolacetic acid and indolbutyric acid (1 mg/l) were tested. The roots type II (20 to 30 mm) and type III ( > 30 mm) were observed after 120 days onto media containing auxins but not in control medium. The regenerated plants were transferred to horticultural earth, peat moss and sand (30:30:40) and the survival of the plants in soil was 80%. The plant adaptation was complete and the first flowering was observed after 1 year in greenhouse conditions. The procedure developed is an alternative to the successful propagation of A. kotschoubeyanus and reduces the risk of extinction of this species.

The taxonomically controversial monotypic genus Chortolirion A.Berger (Asphodelaceae: Alooideae), with Chortolirion angolense (Baker) A.Berger as the only species, has a wide geographical distribution range in southern and south tropical Africa. This may seem to indicate that it would respond to a broad suite of environmental conditions in cultivation. However, the species remains little known in botanical gardens and private collections. This paper reports on the results of cultivation trials aimed at improving seed germination, one of the few reliable propagation mechanisms, given that bulb division often leads to the demise of both stock and cuttings. Application of smoke derived from grass fires significantly enhanced germination rates of seeds, which nonetheless remained as low as between 30 and 40%. Irrigation of seeds in trays with water infused with smoke discs was less successful.

Members of the cactus subfamily Opuntioideae have adapted to numerous types of xeric habitat. Wood evolution was extensive and affected most wood characters. There was a reduction or elimination of xylary fibres, accompanied by a large increase in water storage cells within the wood itself in many of the most xericadapted clades. In all species at least some water storage tissue consists of living parenchyma cells but in most there is also a significant amount of non-living wide-band tracheids (WBTs). Depending on the species, both parenchyma and WBTs occur in the axial tissues alongside vessels or in rays or in both locations. In almost all species, primary xylem is surrounded by a mass of WBTs in the pith and innermost regions of medullary rays. Xylary water storage tissues are especially important to opuntioids because they lack many extraxylary adaptations present in other cacti, so water must be stored in the wood itself. Also, because most opuntioids have only rudimentary leaves and lack cortical bundles, water must be unloaded directly from wood vessels rather than from an extensive network of primary vascular bundles; this adds importance to having parenchyma cells adjacent to wood vessels.

Aloe rendilliorum is a small shrubby species with unspotted rough-textured leaves and a sparsely branching panicle of pink flowers. It is closely related to A. archeri and A. tugenensis, but is a smaller plant and occurs further north, in the territory of the Rendille people.

The first report of a new locality for Pelecyphora strobiliformis in the state of San Luis Potosi, Mexico, was published by the authors in 2000. Later they found other localities that required significant modification to the overall distribution and the conservation status of the species. The taxon is located to the north of the state, in the municipalities of Catorce, Cedral and Vanegas; on hills with calcareous soils, of sedimentary origin, slope of 0 to 25%, altitude of 1780 to 2140 m; dry temperate climate and xerophytic vegetation. The spatial distribution is in colonies or patches. The area of geographical distribution is 800 km²; the area occupied by the colonies is considered to be 0.225 km², with a population from 2 to 3 million mature plants. The seedlings are covered by gravels. The negative impacts do not affect this taxon directly. The conservation status, applying the Mexican Norma Official approaches and those of the IUCN at regional level, are classified as: Not Threatened and Least Concern (L/C) for the state of San Luis Potosí.

The many published infrageneric names of the genus Frailea are a consequence of the high intraspecific diversity, but low diversity within local populations. This can be explained by the specific ecology and reproductive biology, in this combination unique within the family Cactaceae. Fraileas can be classified ecologically as stress-tolerant ruderals. The recently published Frailea mammifera subsp. angelesiae is presented here in detail, and a species from Paraguay, Frailea alexandri, is described here as new to science. Some Frailea names are typified here to stabilize use of the names.