Mammillaria lasiacantha or not?

Abstract

Introduction The specific epithet lasiacantha comes from a combination of two Latin words: the prefix lasior lasio-, which means hairy, or woolly, and the more familiar term acanthus, meaning spine. Many people might think of it as meaning like the hair on Oreocereus, Cephalocereus or similar-looking plants, but lasiacanthus means hairy-spined, that is, with the spines themselves being hairy. Some specimens have spination that is extreme, so much that you could call them plumose – feathery – rather than simply hairy. The related word pubescent means covered with short, soft hairs; downy. Over the years the description of M. lasiacantha has seemingly changed quite a bit, summarized in table 1. Note that the number of radial spines remained at 40-60 for quite a few years. Then, the number goes up to 80, as it was originally described. Also the flower size stays close to 12 or 13 mm long and wide until 1990, when Earle’s book was revised. Then it changes from 12 or 13 mm across to 18.5 mm across. In 1999 Pilbeam kicked the size of the flower up by 2 mm to 20 mm in diameter, despite saying that ‘the size given was 13 mm wide’. In 2001 Anderson maintained the flower size at 13 mm long and wide. When ssp. hyalina was included under M. lasiacantha, the spine count changed, lowered to 26-80. Hunt copied Anderson in the spine count and has the flowers ranging from 9 mm long, 20 mm wide to 6 mm long and 19 mm wide. However, the number of central spines remained at zero all the way through, until you get to 2006, when Hunt included M. magallanii and M. stellade-tacubaya under M. lasiacantha. So, now there is a central spine that is hooked in some forms of the plants, despite the original description saying that the spines were omnibus radiantibus, which means all radial.