Elna secundum Macrum enula vulgo.
Elna, according to Macer Floridus, is the common people’s pronunciation of Latin enula.
Simon refers to verse 1489 of Macer Floridus, here quoted from Choulant’s edition, p.89:
1489 Enula, quam Graecus Elnam (vocat Eleniumque 1490 Dicitur a medicis,… - the bracketed section is not included by Simon)
"Enula, which the Greek calls ‘elna’ (and ‘elenium’ // as it is called by the physicians”) Verse 1489 is very divergent in the different codices and Choulant mentions the vv.ll. in the annotations to Elna: Inula, Elnum, elnam, elenam, helenon.
Simon says that ‘elna’ is the word used “vulgo’, i.e. by the “common people” whereas Choulant’s verson has that ‘Graecus’, “a Greek speaker”, would say ‘elna’.
However, Choulant’s apparaticus criticus does mention a variant reading: Enula, quam vulgus Elnam vocat. "Enula, which the common people call ‘elna’”, i.e. Simon’s version, which makes much more sense since there is no documented Greek variant form “elna”. In fact Ernout/ Meillet mention under ‘inula’ that forms like elna, ella, enula can be found in glosses.
Ultimately, the word is derived from Greek ἑλένιον /helénion/ for which Liddell & Scott attribute multiple botanical identifcations: Calamintha incana “calamint”; also “elecampane”, and finally they gloss it as a synonym to σύμφυτον /sýmphyton/, which itself has multiple meanings.
Inula and its Greek source ἑλένιον /helénion/ have both survived into botanical Latin in the Linnaean plant name Inula helenium L., “elecampane”, and there is a reasonable chance that Simon was indeed thinking of this plant.
CHOULANT, LUDOVICUS (1832) “MACER FLORIDUS de viribus herbarum. Una cum WALAFRIDI STRABONIS, OTHONIS CREMONENSIS et IOANNIS FOLCZ Carminibus Similis Argumenti, Quae secundum codices manuscriptos et veteres editiones recensuit, supplevit et adnotatione critica instruxit Ludovicus Choulant. …. Accedit Anonymi Carmen Graecum “De Herbis”. Sumptibus Leopoldi Vossii. Lipsiae.
ERNOUT, ALFRED et MEILLET, Antoine (2001, retirage de la 4e édition, augmentée d’additions et de corrections par Jacques André) “Dictionnaire étymologique de la langue française”. Klincksieck. Paris.