Well, a global can be taken down. I'd suggest just trying to build the Carrion Woods into the nation.
Also, why Space Algae if they might not be able to start in space? You might want to broaden it to simply a race of sentient plants who can 'uplift' other plants. They might be interesting, though I'm not sure how to differentiate them from the Orcs mechanics-wise. Perhaps Plants could have less chaff (other than through spells like "Uplift Grass" or something; lore-wise smaller, weaker plants have a lower chance of being uplifted) and have to GoR their commanders, going with the 'giving sentience' theme.
Actually, this sounds like a cool idea. They would start with one commander/scout (a multihero, perhaps) and a few units, and have to use a unique GoR spell (for maybe 5 gems) to gain more commanders. Some units would have a domsummon ability, some would be able to use turns to summon more (after being GoR'd, of course). Their only recruitables (and their PD) would be plant-worshipping tribes, with maybe a (bad, obviously) commander and an also-bad mage who could summon a few poor-quality units and GoR them. There could be a minor emphasis on poison.
Trees could be the elite warriors and researchers, some sort of fungus as the assassins and scouts, ivy the poisoners (they would also reproduce quickly), and thing in between these roles (mushrooms which poison and also act as excellent mages, Perhaps crops which would grow slowly but research reasonably well and produce tribal members. Grass would be to chaff as chaff is to elites. They would have all sorts of different units!
I may just do this. Later.
