Nomenclature is a sensitive issue. It is essential that correct names be maintained, and this is the province of the ICBN. The ICBN does have a rule (and I can't quote the ART that covers this, but trust me it's in place) by which original publications with grammatical (orthographic) errors may be corrected (and should be if we are to continue to appear intelligent).
With due respect to Andreas, these sort of decisions should rightly fall to the institution dedicated to this sort of work and there needs to be a central authority to resolve issues like this when they arise. After reviewing Dr. Schlauer's exposition as presented on the Listserve, I support Dr. Schlauer's corrected spelling.
This is a different case than, say, Drosera spatHulata vs spatulata, since both of these Latinizations are correct in their grammar. In this case the original name as used in the Protolouge was not a case of orthographic error, since both are acceptable Latinizations, and the author chose spatulata and we must accept this spelling if we are to be correct.
If you want the "word of god" you *can* trust the ICBN, and although the Savage GArden is a nice beginners book, it is a long ways away from the Bible. The ICBN has worked hard and long to keep us straight over the centuries and they have my support.
P.S. Jim, the proper spelling is Drosera sessilifolia, not sessifolia, lol. Keep on trying, it's all any of us can do.