Mammillaria of the Month

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Mammillaria brachytrychion (mercadensis?)

Mammillaria brachytrychion Lau 1337, straight spined form, in cultivation.  Copyright Chris Davies 2013 
 

Mammillaria brachytrychion Lau 1337, hook spined form, in cultivation. Copyright: Chris Davies 2013

Mammillaria brachytrychion is the name given to a plant discovered by Dr Alfred Lau on the 16th January 1981 pn western facing steep basalt cliffs near General Escobedo in the stat eof Durango, Mexico. At that time it was given the field number Lau 1337, and it wasn't until 1987 that it was given the name Mammillaria brachytrychion by Jonas Luthy in K.a.u.S.

As so often occurs, there is dispute over the attribution of this plant, Dr D. Hunt ascribing it initially to Mammillaria pennispinosa ssp. nazacensis, itself the subject of discussion in some circles as to its relationship to pennispinosa, as well as the validity of some plants bearing that name. In CCC2, it is declared as a synonym of Mammillaria mercadensis. With recent introductions such as Mammillaria thomsonii n.n. it seems as though in central Durango, there are a range of forms whichare interesting and worth further study to determine their relationships.

Clearly a member of the Stylothelae, it appears from plants in collection to be somewhat variable, especially in the presence or not of the single hooked central spine, and also in the degree of offsetting that it does. There are other members of the Stylothelae which exibit this variability, for example Mammillaria scheinvariana. What appears to be consistent are the flowers, which are small, but yellow in colour, and develop quite early in the Spring, to emerge in a good ring around the head of the plant.

It isn't well known in collections, which is a shame, as whatever its taxonomic position, it is a lovely plant, and bearing in mind its cliff dwelling habitat, is best grown relatively carefully, with porous compost and a light hand with the watering can.