The genus and history of names
Plants of the World Online accepts Jasminocereus with one species, J. thouarsii. Nathaniel L. Britton and Joseph N. Rose described the genus in the second volume of The Cactaceae in 1920. Its name refers to the flower's resemblance to jasmine. In their monograph, the species appeared as J. galapagensis, now a synonym of J. thouarsii. [2-WWW] [2-WWW] [Britton and Rose 1920, Britton and Rose, pp. 146–147]
The names J. howellii, J. sclerocarpus and the varieties J. thouarsii var. delicatus and var. sclerocarpus document successive attempts to organise island variation. POWO includes them in one species, along with later subspecies combinations. Older names retain significance when interpreting studies of particular populations. Detailed structure and localities are presented in the species account. [2-WWW]
Tree-like growth form and flower structure
A distinct cylindrical trunk supports the branched upper part of the plant. Thick branches consist of sections separated by constrictions. Low ribs bear round, felted areoles with numerous spines. The slender floral tube opens into a widely spreading perianth. The lower flower region bears small scales, in whose axils the original description recorded small wool tufts. The fruit surface is much less spiny than the stem. [Britton and Rose 1920, p. 146–147]
This structural plan gives a different growth form from the archipelago's other endemic genus, Brachycereus. Stöcklin described Jasminocereus as a columnar cactus reaching around 7 m, while B. nesioticus forms low, densely spined clumps on exposed lava. The comparison concerns the organisation of an adult plant and its place in the island landscape. [Stöcklin 2009, p. 42, 45]
Udokumentowana biologia populacji
Jaramillo and colleagues' study on Santa Cruz demonstrated morning flower opening and the need for an animal to transfer pollen. In the bud-isolation experiment, fruits formed only with free access by visitors. Germination on moist filter paper and on soil, and subsequent seedling growth, were compared separately. These stages define different limitations on population renewal. They are explored in the article on morning pollination and seedlings. [Jaramillo et al. 2010, pp. 22–24]
Evans and Macri compared stem-surface changes on Santa Cruz and San Cristóbal. The two islands showed different strengths of association with exposure direction. Results remain assigned to specific populations, described in the publication under former varietal names. The shared species treatment retains these ecological differences. The study is presented in the article on the stem surface and light. [Evans and Macri 2008, p. 477, 479–481]