Stemonitis spp.

Scientific name:  Stemonitis Gled.
Derivation of name:  
Common name(s):  Chocolate tube slime; Tree hair; Pipe
cleaner slime.
Phylum:   Myxomycota
Order:   Stemonitales
Family:   Stemonitidaceae
Occurrence on wood substrate:  Clustered on dead
wood and leaves; May through October. 
Dimensions: These slime molds are 1-1.5 mm wide and
up to 2 cm tall.  
Description: The brownish, cylindrical top portions
(sporangia) are supported by narrow, black stalks.        
Edibility:  Inedible.
Comments:  Chocolate tube slime look like brown hairs
growing on wood. While not fungi, slime molds often
form spore-bearing structures that resemble those of the
true fungi. Although many slime mold species fruit on wood
they do not form a penetrating and absorptive mass of
hyphae in the wood substrate. Rather, slime molds form
structures called plasmodia which are naked (i.e., without cell
walls) masses of protoplasm which can move and engulf
particles of food in an amoeboid manner. Slime mold
plasmodia creep about over the surfaces of materials,
engulfing bacteria, spores of fungi and plants, protozoa, and
particles of nonliving organic matter. At some point,
plasmodia convert into spore-bearing structures. In
Stemonitis, the plasmodium converts into a clustered mass
of stalked sporangia.

More information at   

Figure 1. A very large fruiting of Stemonits on a log. The
wood serves as a platform on which the plasmodium
forms numerous stalked sporangia. Photo © Gary

Figure 2. A closer view of the specimen in Figure 1. There
are very many individually stalked sporangia clustered
together in this fruiting. Photo © Gary Emberger.

Figure 3. A smaller, more typical cluster of sporangia.
Photo © Gary Emberger.

Figure 4. A close-up of one of the clusters of sporangia in
Figure 3. Each sporangium is supported by a narrow, black
stalk. There are several species of Stemonitis. They vary in
relative length of the stalk and in microscopic details such as
spore morphology. Photo © Gary Emberger.


Figure 5. The stalked sporangia are spore-dispersal
structures. The sporangia become lighter in color as they
lose their dark brown spores. Photo © Gary Emberger.

Figure 6. Appearance of the sporangia following release of
the spores. Attached to a central columella is a network of
capillitial threads. Photo © Gary Emberger.

Figure 7. Immature sporangia. Photo © Steve Nelsen.

Figure 8. Immature sporangia. Photo © Steve Nelsen.

Figure 9. Further development of immature sporangia.
Photo © Linda Sears.


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This page © 2008 by Gary Emberger, Messiah University