More Unusual Suspects

All of these, like the first five, are from the arid biome near Ibarra, in Northern Ecuador. I'm completely in the dark as to what they are.

Number one was teensy, flowers about 2 or 3 mm across.
Number two reminds me of buttercups.
Number three is in the Asteracea, but as to where I've no clue
Number four is commonly called feverbark; I think it's a Croton eluteria, but I may be wrong.
Number five has me completely stumpered.

Thanks in advance, guys!

 

#2, I'm fairly certain, is an Oxalis.

 

That makes a lot of sense, given where it was. I'll bet it's an escapee Oxalis tuberosa, aka Oca, which are grown here for their yummy tubers.

 

#5 looks like a Penstemon. Could of course be a related tropical genus.

 

#1 reminds me of the mat-like euphorbias, e.g. E. glyptosperma, E. fendleri, Chamaesyce lata, etc..

Or, failing that, the flowers suggest Polygonacea, again, one of the mat-like ones, e.g. P. aviculare, P. achoreum.

I assume the woody branches are not a part of the plant, or are they?

 

I'm assuming they're a defunct wild potato. Certainly the field I was stomping was full of them.