Can You Parse These For Me Please?

[Cryptomaniac]

18d. Decent English queen caught in a tryst (8) A?E???T?. ADEQUATE fits the def, and see the EQ, but is duate or aduate a tryst? Can't find online.
24 ac Herb said to make basis for sauce. (4) R?U? ROUX is a sauce, but is there a homophone giving name of herb?
2d Platform by the sea's as rickety in the end. (4) ?U?Y. Must be QUAY, and can see the Y but not the rest of it. Latin scholar needed?

[Mamyalynne]

2d Qua - As + last of rickety

24 Rue is a herb, sounds like

[emeritus]

18 E QU in A DATE

[MargoTester]

24 there is a herb called rue sounds like roux

[Mamyalynne]

qua
kweɪ,kwɑː/Submit
conjunctionformal
in the capacity of; as being.
"shareholders qua members may be under obligations to the company"

[dannyk13]

E(English) +Qu(queen) inside date(tryst)
Roux(sounds like rue( a herb)
Quay -Qua(as) + (ricket)y

[Cryptomaniac]

Thanks all - Latin scholars and botanists and chefs supreme.