Lookup from table not working

[RobGroundtruth]

I am creating an app from a database.  The main table (Seed Collection) has a link to another table (Species).  The main table also has two lookup columns that pull data from the Species table - or at least that is what I want to happen - so that when entering data, the first thing the user does is select the Species.  When the user does this, the other fields pull the data in straight away.
It's not happening though.  Any thoughts?

Also, the two lookup fields do not appear in the app form???

[alexandercox]

Are the lookup columns virtual columns? It is a bit hard to diagnose without seeing the Lookup formulae, are you able to share those?

[RobGroundtruth]

Hi Alexander,
I think they are virtual?  I created then in a database by choosing 

   So, when a user chooses a Species in the Seed Collection App, these fields in the Seed Collection app should be updated by getting the data from the specified column in the Species data row.  But they do not appear in the app (i.e. they are not visible) and even in the data record itself they are blank.

[RobGroundtruth]

OK.  I have managed to get the Lookup function to work by another means (using the FORMULA in the app editor.  I used this formula:
lookup([_thisrow].[Species],"Species","SpeciesID","SeedCollectionInstructions")

and that seems to have worked:

but it still doesn't show in the app itself - which is the whole point...

[AleksiAlkio]

When you use that formula either with the app formula or initial value, you need to add new record or modify the existing record to see the calculated value. 

[RobGroundtruth]

No. That didn't work either.  Maybe I'm trying to do something that isn't possible?
I have a species table that has a collection factor in it:

I then have a seed collection app where the user sets the Species right up front.  I want the use the collection factor in a calculation.

The "Lookup()" function does pull it through:

but I can't use that that in any calculation "Process weight" needs to multiply volume by the collection factor (0.4 x 50)