[1] Comment from the scholia to Aristophanes, Birds 238 (see next note). The gloss explains that the second declension noun kla/dos, kla/dou, o( has metaplastic datives in the third declension, as if from the neuter kla/dos, kla/dous, to/, declined like te/kos, te/kous, to/.
[2] Aristophanes, Birds 238-239 (a lyric passage: web address 1): "and those of you [birds] in gardens that have their pasture on branches of ivy".
[3] This dative leads back to a nominative *kla/s, klado/s, instead; its major attestation is in the song "I shall carry my sword in a branch of myrtle", on which see epsilon 1384, phi 592. The latter also comments on the grammar of the form.