Cleistocactus strausii
The cactus prefers free draining soils, strong sunlight, but not high temperatures — in fact it can withstand hard frosts down to -10 °C. In its natural habitat it receives plenty of water during the summer, but almost none over the winter. In cultivation, watering too much in winter often leads to root rot.
Echinocereus rigidissimus
"Echinocereus rigidissimus" natural habitat is distributed abundantly throughout Chihuahua and Sonora in Mexico, as well as in the United States in Arizona and New Mexico. It grows at elevation from 1200 to 2000 metres above sea level (Blum et al. 1998) 
This cactus prefers south facing slopes and is rarely seen on flat ground. It prefers the 1500 meter elevation. Plants are fire resistant from small grass fires but cannot tolerate hotter fires. With perfect habitat, these plants have been seen growing up to 45 centimeters in height. A 2018 measurement of one plant in the Santa Catalina mountains showed a height of 48 centimeters, a record. Flowering occurs from late April to early June depending on the elevation and spring heat. These plants will not flower when stressed but lack of flowering is rare. Their habitat has been negatively affected by cattle, cactus collectors and off road vehicles. These plants are becoming less common in southern Arizona.(S.A. Rasmussen 2018)