when there is reason to presume a sequence to the variants
on any one lemma.
=>
when there is reason to presume a sequence to the variants.
Or: when there is reason to presume a temporal sequence to the variants occurring in a single location.
(Here "lemma" seems to be used for a location of textual variation - I do not think "lemma" is used elsewhere in this sense. The sequence is of course temporal - does this need to be spelled out?)
I see it is wrong to say that this use is not found elsewhere, but it is not a use defined in 12.1.2. What I mean is that the Guidelines say that you can do without lemmas (<lem>), but then uses "lemma" to signify any location of textual variation, which you cannot do without, as in "substantive variants of the lemma".
Agreed that we should remove "on any one lemma" ; done at rev 12611