Found only in cultivation, Harrisia "Jusbertii" is another sprawling climber with infrequently branching stems up to 2.4 inches thick. It is thought to be an intergeneric hybrid between a Harrisia and an Echinopsis. It certainly shares the large flowers of both genera. Though H. "Jusbertii" is a night bloomer and not all Echinopsis are. The flowers are huge and white with brownish outer petals. The plant is also frequently used as grafting stock.
     This is a cutting from one I found in an alley. I recognized it immediately. Xenomorf, a fellow member of the Davesgarden.com gardening forums has allowed me to use his pictures on the site. Thanks, Xeno :-) Also check out a gallery of some of his other pictures in the Galleries/Friends section. Below is a picture of the flowers.