This is the first and I hope only time I've seen this.  I've been taking a lot of fiber tablets (chewable) and eating a lot of tangerine sections lately.  Today my stool looked like small logs with ferns covering them.  I've had no problems with my stomach but haven't been feeling well and my doctor thinks I may be having a reoccurance of Lyme disease.  I've been taking cefuroxime.