In order to increase our embryological knowledge of Pereskia, a genus considered the earliest member of Cactaceae, we followed the development of the flowers and seeds of Pereskia lychnidiflora, a species from southeastern Mexico. We compared our data with that available from other closely related members in the family. The embryological characterization showed that basic features are homogeneous across the family and supported the placement of P. lychnidiflora as a member of one of two Pereskia clades, the one sister to remaining cacti. Our data also supports the hypothesis that within the family Cactaceae, the evolutionary tendency is towards a reduction of the perisperm. A multilayered seed coat was observed in P. lychnidiflora. A novel finding was the presence of stomata along the basal and central part of the ovary, a character that has never been reported before in other members of Pereskia.

Cephalia occasionally have axillary branching in all three tribes of South American cephaliumbearing cacti. I document axillary branching of the cephalium of Espostoa ritteri (synonym: E. lanata), as well as provide three arguments for why axillary branching of cephalia should not be constrained by the physics of having a massive leaning lateral shoot.

Flowers have evolved suites of traits that are associated with the attraction, reward and utilization of particular pollinator types. Specialization on particular pollinator functional group results in a particular combination of floral traits with consequences on plant fitness through efficient pollen delivery and pollen receipt at the population and species level. The aim of this study was to describe the floral morphology, nectar production patterns, floral visitors and natural fruit set in a population of Echeveria rosea Lindley (Crassulaceae) in central Veracruz, Mexico. The floral traits of Echeveria rosea correspond to the typical hummingbird pollination syndrome. The diurnal pattern of accumulated nectar (volume and amount of sugar) produced by the species corresponds to values reported for other hummingbird-pollinated species. Based on observations of foraging behavior, the Garnet-throated Hummingbird (Lamprolaima rhami) seems to be a more effective pollinator than the White-eared Hummingbird (Hylocharis leucotis). Fruit set per plant was high under natural conditions in the studied population of E. rosea. These results corroborate the hypothesis that E. rosea has a specialized hummingbird-pollination system that results in high fruit set under natural conditions.

The cirio (Fouquieria columnaris) is an iconic species of the northern deserts of the Baja California peninsula in Mexico. In response to proposals to harvest cirio for ornamental wood, recent studies have addressed demographic and biogeographic questions concerning the status of this species. Cirio populations measured in the northern part of its range appear to be declining, and the maximum longevity of this species is about 300–400 years. High-resolution mapping shows that the species ranges from 27.48–30.43°N latitude and 112.58–115.59°W longitude, or approximately from southeast of San Quintín in the state of Baja California to Volcán de Las Tres Vírgenes in Baja California Sur. The elevation of this species ranges from near sea level on the coast of the Pacific Ocean to 1,480 m in the Sierra de La Asamblea northwest of Bahía de los Ángeles and less than 1,460 m in the southern Sierra la Libertad. The climatic conditions where this species grows suggests that it may not be as threatened by climate changes as other endemic species more closely tied to specific climatic characteristics.

Several studies have shown the interesting properties of Opuntia spp. (“prickly pears”), although most of this knowledge is based on O. ficus-indica. O. sulphurea is a species that is largely distributed in the Monte region of Argentina, where it has been used as an edible resource, especially in periods of food shortage. This is the first report evaluating the chemical composition of O. sulphurea cladodes. Our results show that cladodes are composed primarily of water, as with most other prickly pears that have been studied, which is consistent with their expected role as water reservoir in desert communities. Ash and protein content in O. sulphurea are consistent with values found for other species of the genus, whereas carbohydrates are well below levels of other Opuntia spp. Finally, the percentage of lipids in O. sulphurea cladodes is larger than in other studied species and fatty acid composition is quite different from observations made in similar studies. These earlier studies showed that linoleic acid is the major constituent of fatty acid fractions, followed by palmitic and oleic acids. Our analyses showed that these fatty acids are also principal constituents of O. sulphurea cladodes, although linolenic acid proved to be the most abundant. Curiously, the previous works found relatively low quantities of this fatty acid. Other minor fatty acids were also detected in cladodes of O. sulphurea, although the percentages are larger than in other studies of prickly pears. We discuss our results in the context of the potential nutraceutical and economic utility of O. sulphurea cladodes as a new source of essential fatty acids, especially in semi-arid areas as the Monte region where this species represents an abundant edible resource which is available even in periods of scarcity.

In the past, members of the Cactaceae family were mostly propagated by seeds or vegetatively by cuttings and grafting. Seeds, however, do not guarantee genetic stability and, in the case of some cacti, seeds are difficult to obtain, their germination rates are low, or they need to be stored for a long time in specific light and temperature conditions. Traditional vegetative reproduction in vivo, on the other hand, may be less efficient insofar as a limited number of plants can be obtained. Major issues associated with traditional propagation methods may be solved by the use of plant tissue culture. Today micropropagation techniques are applied in order to produce large numbers of new high-quality plants in a relatively short time and space. This is especially important for endangered and desirable species such as cacti. This paper discusses the achievements, current state and future prospects of cactus micropropagation methods. We also provide an overview of cactus multiplication by areole activation, direct and indirect organogenesis (caulogenesis and rhizogenesis) and somatic embryogenesis, as well as consider acclimatization. Micropropagation of cacti is still sufficiently idiosyncratic that different protocols must be used for different species, even closely related ones.

Agave azurea, a new species of Agave from the Picachos de Santa Clara, Baja California Sur, México, is a medium-sized species with distinctive glaucous blue-green leaves that does not produce offsets, has a relatively short and narrow inflorescence, and a distinctive flower structure. The closest relative to this new species is Agave vizcainoensis, which occurs to the west on the Vizcaino Peninsula. This new species is a narrow endemic restricted to mostly rocky slopes and alluvial surfaces emanating from isolated mesas and peaks in an environment with strong fog influence. Agave azurea does not appear to be threatened by habitat modification. Field examinations and a review of herbarium specimens assigned to Agave vizcainoensis, A. sebastiana, and A. gigantensis led us to conclude that A. sebastiana is restricted to off-shore islands, A. vizcainoensis occurs on the western Vizcaino Peninsula, and A. gigantensis is restricted to the northern Sierra de la Giganta.

The species of Huernia with smallish flowers that occur in the Horn of North-East Africa and on the adjacent Arabian Peninsula are reviewed. The following new species are published here: Huernia sudanensis Plowes, Huernia delicata Plowes, Huernia yemenensis Plowes, and Huernia baradii Plowes, and comments are provided about other previously known small-flowered species of Huernia from that region.