Four species and their identification
The genus contains Myrtillocactus geometrizans, M. schenckii, M. eichlamii and M. cochal. A short trunk and developed crown are especially apparent in mature plants. The ribs carry areoles, small areas from which spines and flowers develop. Comparing stem colour, areole spacing and spine structure together helps distinguish species. [Britton and Rose 1920] [2-WWW]
Young stems of M. geometrizans have a pronounced bluish tint, and the central spine can be flattened and much longer than the radials. In M. schenckii, stems are dark green and areoles closely spaced. M. cochal has a lower, spreading habit and short spines. M. eichlamii develops broad six-ribbed stems and cream flowers. [Britton and Rose 1920]
Small flowers on large plants
Flowers have a short tubular portion and widely spreading tepals. Several flowers grouped on one areole can subsequently produce a cluster of fruits. Observations of M. schenckii show that opening time and duration also vary with season. In spring, flowers in the studied population remained open for about 11 hours on average, while some flowers observed in winter lasted longer. [Britton and Rose 1920] [Ortíz et al. 2010]
Fruits in ecosystems and human use
The fleshy fruits contain small, dark seeds. In Mexico, fruits of M. geometrizans and M. schenckii are known as garambullo. Research on M. schenckii in the Tehuacán Valley documents retention of desirable plants in agricultural landscapes and their cultivation in gardens. Fruits of M. geometrizans also provide feeding sites and shelter for diverse arthropod assemblages. These separate studies describe particular species and local populations within the genus. [Britton and Rose 1920] [Blancas et al. 2009] [Sanjuan-Trejo et al. 2021]