ACROSS

 1  How you might find some stands in the park, if really wild! (4,7)

 9  and 10 First class, as Fido might get to sniff things out. (2,2,5)

11  The thing the unknowing are in. (4)

12  Foreign money found in most of Florida, and a couple of other points. (7)

13  Mean! Ink, as they say, if your head is tacked on. (7)

15  The better type might be found here, to closely follow what the train is on. (3,5)

16  Concerning old songs and poetry, you might find them on the last part of 15. (6)

18  The song comes back to be with mystical knowledge. (6)

21  How you sometimes can’t get a word in, if knowledgeable about the slight advantage. (8)

24  The one of Samothrace celebrated such winning ways when the old theatre troupe gets conservative. (7)

26  He who founded the city of Thebes was a low-down scoundrel, and real nasty! (7)

28  They really get turned on as a team! (4)

29  Intimidated to marry each other? (5)

30  If you’re worried about something, they say everything will come out in it, according to Shaw, possibly. (4)

31  Knowing what to do in Paris? (6-5)

DOWN

 2  A philosopher who could show another philosopher how to start his will. (9)

 3  Praise be! (Has on an otherwise different appearance, too!) (7)

 4  and 14 They were smiling at me in tune. (4,5)

 5  If confused, infer it from a rather slangy description of the more worthwhile. (7)

 6  A place not far from Salt Lake where you get to go up to study. (5)

 7  Taking a public vote ends up with nothing, according to the old god. (6)

 8  It once meant skillful–now it has a more sly meaning. (6)

14  See 4

17  Could be either the man or the machine, but the sward is all the better for it. (4-5)

19  Gave out the rumor that it could be onside? (6)

20  Title given the little company up and down–but it’s just a big blow! (7)

22  Could be associated with Moses, and a slangy note hurried crazy-mad to make it! (7)

23  A point in your extra wheel covering could be rather hard to find. (6)

25  Possibly stale output from a physicist and inventor. (5)

27  Were wrong, but could hold water. (4)