A Grammatical Dictionary of Botanical Latin

zyg-, zygo-: in Gk. comp., joined, yoked; see -zygus,-zyga,-zygon (adj.A and noun) [> Gk. zygon (s.n.II) = Lat. jugum, the yoke or cross-bar tied by the zygodesmos to the end of the pole, and having zeuglai (collars or loops) at each end, by which two horses, mules or oxen were put to the plough or carriage (Liddell & Scott)]:

- zygomeris,-e (adj.B): with parts joined in pairs; see -ygus,-zyga,-zygon.

Zygocactus, K. Schum., a cactus with zygomorphic flowers; Zygodon Hook. & Tayl., zygos, a pair, and odon, tooth, in allusion to the teeth of the peristome joined in pairs; Zygopetalum Hook., for the yoked or joined petals.

Zygonerion (Apocynaceae)

Ajuga “from the Greek a-, without, and zugos (Latin jugum), yoke, from the seeming absence of a yoke-fellow to the lower lip of the corolla” (Fernald 1950).

Tetrazygia(Miconieae).

Synzygia,-ae (s.f.I): “(obsol.) the point of junction of opposite cotyledons” (Lindley) [> Gk. syn-, united, ‘together’ + > zygon, yoke – yoked together].

NOTE: sometimes zig-, zigo- is used, as in Zigadenus Michx., Gk. zygos, a yoke, and aden, a gland, "the glands being sometimes in pairs" (Fernald 1950).