sprig
From LSJ
προγράψαντες οὖν τά τε θεωρήματα καὶ τὰ ἐπιτάγματα τὰ χρεῖαν ἔχοντα εἰς τὰς ἀποδείξιας αὐτῶν μετὰ ταῦτα γραψοῦμές τοι τὰ προκείμενα → having therefore written at the beginning the theorems and the postulates that are necessary for their proofs, we will then write out for you the propositions
branch: P. and V. πτόρθος, ὁ (Plato), κλών, ὁ (Plato); see branch.
plucking sprigs of tender myrtle for his head: V. δρέπων τερείνης μυρσίνης κάρᾳ πλόκους (Eur., Electra 778).