Distribution and growth form
The native range extends from southern Arizona into northern Mexico. In northern Sinaloa, the species was studied along a gradient from coastal dune scrub through thorn scrub to seasonally dry deciduous forest. This variation among sites provides an important context for comparing reproduction and seed germination [Casillas-Álvarez et al. 2018] [2-WWW].
Plants of the World Online accepts the name Stenocereus thurberi (Engelm.) Buxb. Names encountered in older literature include Cereus thurberi and Marshallocereus thurberi [2-WWW].
Stems flowers and fruits
The plant branches near its base. Green stems usually have 15 to 19 ribs. Funnel-shaped flowers open at night, mostly near the shoot tips. The inner tepals are creamy white to light pink. Red, fleshy fruits measure approximately 45 to 65 mm and bear deciduous spiny areoles [Gibson 2003].
Germination inside the fruit
Seeds of Stenocereus thurberi can begin to germinate inside fruits on the maternal plant. The process takes the form of cryptovivipary, in which the embryo emerges through the seed coat while remaining enclosed within the pericarp. A study of five populations in northern Sinaloa recorded this condition in 100 of 194 plants and 245 of 994 fruits. Most affected fruits contained between one and five precociously germinating seeds. These figures describe the sampled populations during a single reproductive season in 2014 [Casillas-Álvarez et al. 2018].
Seed variation among populations
Precocious germination was also associated with traits of the remaining seeds from the same maternal reproductive category. Under shared laboratory conditions, final germination percentage, germination rate and synchrony varied among populations and reproductive categories. Maternal reproductive category accounted for approximately 5 to 11% of the variance in the measured traits, while population of origin accounted for 63 to 86%. The substantial contribution of differences among sites highlights the importance of seed provenance when comparing germination biology within this species [Casillas-Álvarez et al. 2018].
Related articles
Materials from the author's archive
The species also appears in Konrad Szychowski's private material archive [Romulski 2005a] [Kaktusy i Inne 2006a].
Synonyms and names in the literature
Cereus thurberi · Glandulicereus thurberi · Lemaireocereus thurberi · Marshallocereus thurberi · Neolemaireocereus thurberi · Pilocereus thurberi · Rathbunia thurberi [2-WWW]