Stenocereus gummosus

Distribution and growth form

The native range covers northwestern Mexico. A study comparing this species with S. eruca included plants near San Carlos on the Baja California peninsula and at Punta Onah in Sonora. The authors described a shrubby growth form with partly upright stems and progressively bending lateral branches. This architecture is associated with the development and mechanical support of successive stem portions [Niklas et al. 2003] [2-WWW].

Plants of the World Online accepts the name Stenocereus gummosus (Engelm.) A.C.Gibson & K.E.Horak. Older combinations such as Cereus gummosus and Machaerocereus gummosus refer to the same species [2-WWW].

Collenchyma and stem support

Stems of Stenocereus gummosus obtain substantial mechanical support from their peripheral tissues. Compared with S. eruca, their epidermis and collenchyma formed a complex with a higher elastic modulus, breaking stress and extensibility. Collenchyma was more strongly developed along the sides and crests of the ribs. This peripheral placement increases its contribution to carrying the stresses generated during bending [Niklas et al. 2003].

Secondary growth and stem rooting

Secondary growth and wood became more important with stem age, particularly in the oldest portions of S. gummosus. The investigators also observed that lateral branches bent progressively as they elongated. Portions touching the ground could develop adventitious roots and occasionally detach from the maternal plant. The species therefore combines support of partly upright stems with the capacity to root stem portions lying near the soil surface [Niklas et al. 2003].

Materials from the author's archive

The species also appears in Konrad Szychowski's private material archive [Gorelick 2007] [Kaktusy i Inne 2006a].