Software: Ideatree  

Author: ProtoSoft, Inc.  
Supported: Unknown  
Platform: MS-DOS  
Language: C  
Derived from: Citadel  
See also: Citadel-128  

Ideatree was commercial software. I remember calling it once or twice, but don't remember much about it. 

I included the "See also" to Citadel-128 because Ideatree is mentioned there. That's one of the few places I've ever seen it even mentioned.