Here is a list of further resources that you might find helpful.
Cacti & Succulents
Connecticut Cactus & Succulent Society: The
club I belong to and was President of from 2001-2003.
Growing Tropical Plants in Phoenix: My favorite
feature is the ability to look up info about plants by
botanical name or
common name.
The Genus Echinofossulocactus: A site dedicated
to Echinofossulocactus (Stenocactus).
Succulent Euphorbias: A site dedicated
to succulent Euphorbias with many photos and growing requirements.
The Amateurs' Digest
The Cactus Mall
Aroids
International Aroid Society: Please consider joining the
International Aroid Society. Their web site has lots of information about Amorphophallus, Typhonium, Philodendron, Calladium,
Colocasia, Alocasia, and all the other aroids. Membership is cheap and includes a nice newsletter.
Click for membership form, you can send a check or use PayPal.