Echinocereus pulchellus

Stem, areoles and spines

The 2020 description presents usually solitary plants with a depressed globose stem bearing 10–12 ribs. The areoles, from which spines arise and buds develop, are round. Most described specimens have 3–5 radial spines, with higher counts recorded less frequently. The spines are subulate, rigid and short, usually 1–3 mm long. They range from yellow to grey and may be shed as the areoles age. [Sánchez et al. 2020]

The similar Echinocereus acanthosetus has broadly elliptic areoles and more numerous fine, bristle like spines. Echinocereus sharpii differs in its more numerous ribs and spines and predominantly pale flowers. In Echinocereus weinbergii, spines are usually thicker and the floral tube is wider than long. Identification uses a combination of stem and floral characters because some measurement ranges overlap between species. [Sánchez et al. 2020]

Flower, fruit and developmental rhythm

Flowers have magenta tepals, occasionally pale pink. Their tube is longer than wide, the staminal filaments and style are white, and the stigma lobes are green. In the described material, flowers were 27–45 mm in diameter, so their spread could approach or exceed the width of the stem. These values come from the taxonomic treatment and describe the material examined there. [Sánchez et al. 2020]

At the localities included in the revision, flowering occurred in March and April and fruiting from April to June. The fruits contain small seeds. These seasonal dates describe plants in their Mexican environment. In a collection, flowering time should be interpreted in relation to actual growth resumption and the conditions in which plants are maintained. [Sánchez et al. 2020]

Habitat and species boundaries

The species grows in grassy patches within xerophytic scrub near the boundary between the Sierra Madre Oriental and the Trans Mexican Volcanic Belt. Site soils were described as derived from both igneous rocks and limestone. Remaining patches of natural vegetation are separated by transformed land. The revision identified urban growth, agriculture and rock extraction as causes of habitat loss in the studied populations. [Sánchez et al. 2020]

The former broad circumscription of Echinocereus pulchellus included populations now assigned to other species. The revision compared 50 morphological characters in ten populations representing five formerly recognised subspecies. Its authors distinguished E. acanthosetus, E. pulchellus, E. sharpii and E. weinbergii. POWO accepts each of these names at species rank. An older collection label therefore needs to be interpreted together with the specimen’s provenance and characters. [Sánchez et al. 2020] [2-WWW] [2-WWW] [2-WWW] [2-WWW]

Narrowing species limits also changes the interpretation of conservation evidence. The revision distinguishes earlier assessments of the broadly defined complex from its own assessment of Echinocereus pulchellus populations in Hidalgo and Puebla. Population and habitat loss data are assigned to this narrower circumscription. [Sánchez et al. 2020]

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