Sumac (Rhus lancea - a common landscape tree in the low desert) leaves should be fine, although don't use the leaves of 'poison sumac' (Rhus vernix or Toxicodendron vernix). Even eucalyptus and oleander leaves can be composted.

Here's research from the University of Arizona -
The Sept/Nov 1999 issue of the trade journal Southwest Horticulture had an article about compost made with oleander and eucalyptus. Dr. Jimmy Tipton and Libby Davison from the Dept. of Plant Science University of Arizona conducted these tests.

The following are quotes from that article.

"There was no apparent phytotoxic effect of either eucalyptus or oleander compost. In fact, plant characteristics generally increased with increasing portion of either in the medium. Plants grown in a medium containing either compost were not significantly different from, or were superior to, plants grown in CM (commercially-available medium)."

"These results suggest that whatever phytotoxic compounds that may be present in eucalyptus or oleander were destroyed by composting."

I have one answer for African Sumac questions: Chop it down. I had 7 of them in my backyard when I bought the house. They're incredibly messy. I'm not crazy about them. I do however use the leaves and the berries in the compost all the time without problems.

The berries are also good for making a type of beer or juice. They have a sweet/sour taste. I tried it once. Wasn't bad, but nothin' to write home about.