Sporangia of many myxomycetes are easily obtained by placing chips of tree bark in a moist chamber (e.g. petri dish with bottom lined with moist paper towel or filter paper). After a few days or weeks sporangia may appear. This simple method is said to yield sporangia any time of year.  For more detailed description of procedure see   Stephenson and Stempen's 1994 book Myxomycetes. A Handbook of Slime Molds and the more recent Myxomycetes of Ohio:  Their Systematics, Biology, and Use in Teaching by Harold W. Keller and Karl L. Braun (Volume 13, Number 2 of the Bulletin of the Ohio Biological Survey, New Series).

Procedure:

1. Collect postage stamp-sized chips of tree bark from different trees. Use fingers or a screwdriver to flake off chips of outer bark. [Be careful if you use a pocket knife! Scrapping knuckles and jabbing knife blades into hands are likely to happen if you are not mindful of potential mishaps.] You can also try chips taken from logs or woody debris on the forest floor. Collect several chips from a tree and place chips in a paper bag and label bag with date, location, and type of tree (e.g. white oak, red maple, log, etc.). Collect from a several tree species, different compass directions, various heights above ground, or from different forest types.

2. Label petri dishes so that you know the details of the collection (date/tree species/etc.).

3. Place chips in petri dish and fill with distilled water to cover samples. Cover with lid and let soak overnight.

4. Cut 2-3 sheets of white paper towels to fit in bottom of petri dishes.

5. After 8-12 hours of soaking, pour off water and remove chips. Line bottom of petri dishes with 2-3 layers of precut white paper towel.. Arrange chips (outer bark up) over lined bottom so that the chips aren't touching each other. Add additional water if necessary to leave petri dish chambers moist but without freestanding water. Leave with lids on for 1-2(3) weeks storing at room temperature with diffuse lighting.

6. Check daily. Be sure to occasionally add additional moisture if chambers start to dry.