Background:

The genus Coryphantha has the second largest number of species of the tribe Cacteae-Cactaceae. Morphologically, it has been reported that the stem presents mainly globose, ovoid and cylindric variations. However, at the anatomical level, descriptions are scarce and focused on particular tissues (epidermis or xylem). The aim of this work is to contribute to the anatomical knowledge of the genus.

Questions and/or Hypotheses:

What are the anatomical characteristics that differentiate one species from another? Does the presence of crystals allow differentiation between species?

Study species:

Coryphantha clavata, Coryphantha cornifera and Coryphantha radians.

Site and years of study:

San Luis Potosí and Querétaro, Mexico; 2017, 2020.

Methods:

Three individuals per species were collected, and conventional histological techniques were applied. Anatomical descriptions were made for different tissues, and structural characteristics were measured for each species.

Results:

The species exhibited the greatest differences in the epidermis and hypodermis, such as the presence of subepidermal stomata (C. radians), three-layered hypodermis (C. clavata), and non-collenchymatous hypodermis (C. cornifera). Crystals were not observed in the epidermises but instead in the hypodermes, which exhibited crystal shapes of druses (C. cornifera and C. radians), prisms and round bodies (C. clavata). In the cortical tissue, C. clavata had abundant mucilage cells. The observed xylem and phloem tissues exhibited characteristics similar to those of other Coryphantha species.

Conclusions:

The anatomical characteristics of the epidermis and hypodermis are considered of high systematic value and could be used to distinguish between species of the genus.