An obscure lexicon

I'm searching in vain for information on a work known as the Lexicon Patmense, alternately known as Λέξεις μεθ’ ἱστοριῶν ἐκ τῶν Δημοσθένους καὶ Αἰσχίνου λόγων or Lexicon in Demosthenem et Aeschinem. So far L'Année and Jstor have turned up nothing, and Google hasn't been much better.

Any ideas? According to the TLG, where I found the text, it was published as part of Sakkelion's Lexica Graeaca minora, Olms 1965. The TLG gives the date as uncertain.

At the moment I'm in a little suburban town without a good library, and I'm trying to find out the opinions any scholars might have regarding its date and provenance. My early efforts working strictly from the text have been frustrating.

The lexicon cites Nicander for the notion that fennel is attractive to snakes, because they doff their slough upon it (apologies to Seuss):

Καὶ ἡ μὲν μάραθρος ὄφεων ἀγωγός ἐστι διὰ τὴν ὀσμήν· Νίκανδρος γάρ
φησιν ὅτι ἐπὶ τῆς μαράθρου οἱ ὄφεις τὸ γῆρας ἀποδύονται.

This is an odd statement and a clear case of a misreading. Nicander says that snakes in springtime rejuvenate themselves in part by eating fennel (Th. 31). This establishes that they find it attractive, though there's no mention of their slough. But much later, while discussing the Amphisbaena, a mythical snake with a twin head upon its tail, he says that in springtime, when 'earth reveals serpents,' the amphisbaena 'does not feed upon a flowing shoot of fennel spray when it casts flesh round its body 'neath the sun.'

οὐδ’ ἄρ’, ὅταν χαράδρεια λίπῃ καὶ ῥωγάδα κοίλην
ἦρος ἀεξομένου ὁπόθ’ ἑρπετὰ γαῖα φαείνῃ, (390)
ἀκρεμόνος μαράθοιο χυτὸν περιβόσκεται ἔρνος,
εὖτ’ ἂν ὑπ’ ἠελίοιο περὶ φλόον ἅψεα βάλλῃ,
ἀλλ’ ἥγ’ ἀρπέζαις τε καὶ ἐν νεμέεσσι πεσοῦσα
φωλεύει βαθύυπνος, ἀπ’ εἰκαίης δὲ βοτεῖται
γαίης οὐδ’ ἀπὸ δίψος ἀλέξεται ἱεμένη περ.

He's clearly contrasting the amphisbaena with more typical snakes, and the fennel is recalled not because it relates to sloughing skin in any way, but because the amphisbaena's odd behavior, not eating fennel in spring, sets it apart. That last temporal clause is to be negated along with the eating of fennel, not taken as a positive. It fleshes out the idea of springtime, a time of rejuvenation. This is a common use of such clauses in Nicander, who tends to use them to add vivid images to a subject not rich in narrative potential.

The amphisbaena neither eats fennel, nor does what other snakes do in springtime, namely put on their new skin.

The interpretation is confused, I suspect in part due to the poor state of Nicander's text in the early Byzantine period. It was once described as 'illegible' and virtually written in a foreign tongue before the Palaeologan renaissance, and in such a corrupted state it would have been easier to misinterpret the passage.

But I'd like to be more certain about the date of the Lexicon before I make too much of it.