Growth form and taxonomic position
The genus belongs to Cylindropuntieae. Stems become woody and leaves have fleshy blades. Areoles produce spines and glochids. Molecular studies place this lineage among opuntioids and allow its leafy habit to be analysed alongside closely related forms with more strongly reduced leaves. [Taylor et al. 2026] [Majure et al. 2019] [Majure et al. 2023]
Trzy opisane gatunki
Q. verticillata occurs in eastern Bolivia, western Paraguay and northwestern Argentina, in the eastern Andes and Chaco region. Q. zehntneri grows in southern parts of the Brazilian Caatinga, especially on limestone in the São Francisco valley. Q. pelodaserra, described in 2026, is known from limestone outcrops around Irecê in Bahia state. [Taylor et al. 2026]
POWO, checked on 9 October 2026, still included the two previously known species. The Q. pelodaserra profile is based on the published protologue, explicitly giving the name's authors and the source of the description. [2-WWW] [Taylor et al. 2026]
Different sets of floral characters
The two previously known species have pink to purple flowers opening during the day. In Q. pelodaserra, white flowers open in the evening and have a covered nectar chamber. The authors associated this character set with the hypothesis of chiropterophily, pollination by bats. [Taylor et al. 2026]
Leaf physiology
Q. verticillata (Q. chacoensis in the 1987 experiment) changes the timing of CO₂ uptake in response to drought. Later acidity measurements demonstrated a contribution from nocturnal carbon recycling even while atmospheric uptake continued. These are data for this species, describing leaf and stem physiology separately. [Nobel and Hartsock 1987] [Martin and Wallace 2000] [2-WWW]