Hi Steve
We don't support a select drop down in the species grid at the moment, since select drop downs are normally used for short lists of things, and short lists can be loaded straight into the grid. Though of course we'd welcome anyone who wants to try updating the code.

One alternative might be to put 2 species grids on the same page, making it clear that the first is for the species you are expecting them to record and the second is for additionals that they might record if they want to.

Using a dynamic form, here are the relevant bits of the form structure that are from an example form with 2 grids:

?Please record the animals (excluding galls) you saw below.?
[species]
@id=animals
@resizeWidth=1500
@resizeHeight=1500
@attributeIds=[54,93,164,165,166,18]
=Plants, galls, fungi and lichens=
?Please record the plants, plant galls, fungi and lichens you saw below.?
[species]
@id=plants-etc
@resizeWidth=1500
@resizeHeight=1500
@attributeIds=[54,93,167,168,18]

Basically you can add any number of [species] controls to the form, but if you do, override the @id option to ensure they are all unique. You can then give each grid a different set of attributes by using the @attributeIds option to select a subset of the attributes available in this survey. In your case you’d want to set a different @lookupListId to the ID for the list to load into each grid.

Note that you'll want a recent update from SVN in your client helpers to do this.

Best wishes
John