I love those little details about races - it can make a real difference and give you a good handle to get some roleplayiing mileage out of them. But sometimes the concept is enough - I've played Dragonstar (3.5 D&D in space, where the dragons rule everything and drow are the secret service), and one of my favourite races in there is the Sathoni. I mean, who can't respect a plant species that carved out an empire of thousands of star systems, but who, when given a chance, will prefer to just lie in the sun, combining the effects of a good lunch and a nap all in one?!
However, it was clearly only put in as a concept race, and some detail was glossed over. I had a great time (the GM less so) in fleshing out some of the ways in which the race worked... Yes, they photosynthesise, and eat soil, but what about excretion? Plants don't 'eat' soil, they just perform mineral exchange. Plants gain energy from carbon dioxide - does this mean that on a Sathoni ship CO2 is the main atmospheric component? If they have lived on a planet for a long time, do they have to move off it eventually because of global cooling as so many of them are taking in the carbon dioxide in the atmosphere? Glorious details, in my opinion
