Echinocactus: botanical profile
Quick answer
Echinocactus (Link & Otto 1827) includes usually globose plants becoming oblong or stout-cylindrical, mostly with spine-bearing ribs (sometimes represented only by vertical or spiral rows of tubercles). Flower-bearing areolae are usually contiguous to the young spine-bearing areolae and just above them, sometimes connected by a short groove, rarely in the axil of a tubercle. Ovary bears scales which are naked or woolly in the axils; fruit succulent or dry; seeds often albuminous; embryo usually curved with foliaceous cotyledons. Related genera include Astrophytum, Gymnocalycium, and Malacocarpus. The genus merges into neighboring genera, with mamillate forms intermediate between Cactus and Echinocactus.
Start here:
- 1. Identify by ribbed (not tuberculate) stem surface - ribs 8-27 in most species
- 2. Flowers emerge from areolae at the top of ribs, adjacent to spine clusters
botanical profile for Echinocactus
Echinocactus (Link & Otto 1827) includes usually globose plants becoming oblong or stout-cylindrical, mostly with spine-bearing ribs (sometimes represented only by vertical or spiral rows of tubercles). Flower-bearing areolae are usually contiguous to the young spine-bearing areolae and just above them, sometimes connected by a short groove, rarely in the axil of a tubercle. Ovary bears scales which are naked or woolly in the axils; fruit succulent or dry; seeds often albuminous; embryo usually curved with foliaceous cotyledons. Related genera include Astrophytum, Gymnocalycium, and Malacocarpus. The genus merges into neighboring genera, with mamillate forms intermediate between Cactus and Echinocactus.
How to handle botanical profile on Echinocactus
- 1
Identify by ribbed (not tuberculate) stem surface - ribs 8-27 in most species
- 2
Flowers emerge from areolae at the top of ribs, adjacent to spine clusters
- 3
Check ovary scales: subulate and woolly in axils for dry-fruited species, ovate/cordate for scaly non-woolly fruit
- 4
Note spine characters: rigid and annulate, not hooked; central spines often flat and stout with lower one recurved
Ongoing Echinocactus notes
Echinocactus species require intense light, minimal water, and fast-draining mineral soil. As desert plants from the southwestern US and Mexico, they tolerate extreme drought but rot quickly in moist conditions. Water only when soil is completely dry and provide maximum light exposure.