Austrocylindropuntia subulata (Muehlenpf.) Backeb. (Cactaceae, Opuntioideae): an invasive new cactus record to the flora of Saudi Arabia.

Austrocylindropuntia subulata is an invasive new opuntioid cactus to the flora of Saudi Arabia collected from Al-Sarah highlands (south-western region). This is the second cylindrical cactus from the Cactus family recorded in the Kingdom after the discovery of Cylindropuntia rosea in the same region. It differs from C. rosea by lacking of jointed stem and absence of the spines sheath and having long conspicuous leaves. The plant was not widespread in the region. It is only confined to a limited protected area at an elevation of 1630-2160 m above sea level. Taxonomic key, general descriptions, diagnostic features and colored photographs are provided. As A. subulata is one of the restricted invasive plants worldwide, actions must be taken by the government to restrict the spreading risks of this taxon into the environment. No records have found regarding the uses of this species by the native people. Eradication steps should be taken to minimize its further distribution in the productive regions of the Kingdom. [ABSTRACT FROM AUTHOR]