A new geophytic species of the genus Tephrocactus from northern Argentina, T. abditus, is described with the evaluation of its morphological data. The species is likely to be closely related to Tephrocactus weberi, but it markedly differs by its strictly subterranean growth, thickened and contractile tuberous roots, and short pectinate spination without central spines. The flowers are similar to those of T. weberi regarding their shape as well as range of flower colors (from yellow to red).

The mesembs are a very large group of succulents, with the majority native to southern Africa. The name “mesembs” derives from the old family name Mesembryanthemaceae, but now these plants are put into the family Aizoaceae, which includes some weedy annuals along with the succulent marvels which are widely grown by plant fanciers around the world. Among the collectable kinds are the Living Rocks (Lithops), Baby Toes (Fenestraria), Split Rocks (Pleiospilos) and Tiger Jaws (Faucaria). Plants in the family are often referred to as “ice plants”, and this designation refers to the highly reflective papillae, or tiny bumps, which cover the leaves of some species and make them look as though they were sprinkled with salt or ice crystals. The book Mesembs of the World, published in 1998, lists about 1800 recognized taxa (species, subspecies and varieties), but the list of published names is far longer than this, since many older names are now considered to be synonyms. Here, five of the less-common species are presented.

In 1923, Britton & Rose, in their epic Cactaceae, created the genus Dolichothele, with the type of the genus being D. longimamma, described almost a hundred years prior as a Mammillaria. They also included M. sphaerica. and M. uberiformis. The generic name alluded to the long (greek Δόλιχος, Dolichos) tubercles (greek, θηλή, Thili). Other authors subsequently added M. melaleuca, M. surclosa, M. baumii and M. carretii amongst others. At the time they were segregated on the basis of their flowers, but today we know they also share sweetly scented flowers and thickened roots, compared to many other species of Mammillaria.