Ribs usually 3, rarely 4, thick.
Joints 8 to 10 cm. wide, deeply crenate; spines very stout, subulate.
Spines 1 to 6; perianth-tube about 7 cm, long 1. A. horridus
Spines about 10, the outer 5 to 8, very short; perianth-tube about 12 cm. long 2. A. colombianus
Joints 2 to 8 cm. wide, low-crenate; spines slender.
Spines well developed, subulate 3. A. pentagonus
Spines short or none, when present acicular 4. A. subinermis
Ribs 4 to 7, mostly thin. Plants green.
Spines up to 7 cm. long; ribs to 5 5. A. occidentalis
Spines 3 cm. long or less; ribs 5 to 7 6. A. brasiliensis
Plants bluish white; joints 4-angled; spines 2 to 6, the longest 2 cm. long 7. A. albicaulis
Was this article helpful?
You Might Just End Up Spending More Time In Planning Your Greenhouse Than Your Home Don’t Blame Us If Your Wife Gets Mad. Don't Be A Conventional Greenhouse Dreamer! Come Out Of The Mould, Build Your Own And Let Your Greenhouse Give A Better Yield Than Any Other In Town! Discover How You Can Start Your Own Greenhouse With Healthier Plants… Anytime Of The Year!