REMEMBER THE FURBISH lousewort? The rare, scraggly snapdragon that was found along the Upper St. John River in Maine and for a while seemed to have stalled the proposed Dickey - Lincoln hydroelectric project? We remember it vividly because environmentalists raised a howl last spring when we suggested that even if the lousewort were an endangered species, that alone should no dictate the fate of the dam. We weren't against the idea of saving as many plants as possible. What troubled us was the sense of values that placed the lousewort ahead of the hydroelectric project. It struck us as a prime example of a dogmatic and narrow approach to situations in which many environmental, economic and other elements should be weighed.

The lousewort came to mind the other day as we started to catch up with the Council on Environmental Quality's attempts to overhaul the environmental-impact-statement process. Like nearly everbody else, CEQ recognizes that matters have gotten out of hand. Statements are much too cumbersome; production of the proper documents often becomes a substitute for the timely analysts of alternatives that the law was meant to spark.

CEQ is proposing, among other things, to limit the length of statements, set standard formats, and get agencies and levels of government to work together more. Most important, CEQ wants to require more hard analysis and less of the tedious listing of every bit of flora and fauna that a road or dam or other project might affect.

All that is good. But CEQ has not stopped there. Its proposed rules also declare that in every case the government should choose the course of action most beneficial or least harmful to the environment - or else, as one draft puts it, explain "the reasons why other specific considerations of national policy over - rode the environmentally preferable alternative." And that's what seems to us to go too far along the line of louseworts-over-dams. Granted, the language is not as absolute as the requirement that endangered species shall not be destroyed. But it sets up such a stern test, and in such sweeping terms, that it would put a very heavy environmental thumb on the decision - making scales. It would also bring on years of litigation over the meaning of every word - and that's perhaps the surest way to bring the whole assessment process tumbling down.

As it happens, there is a useful lesson in the lousewort fight. It seems that since last spring, more clumps of louseworts have been found elsewhere in Maine, so the species might survive even if Dickey - Lincoln is built. Meanwhile, the government has produced an environmental impact statement which, while much bulkier than CEQ's new proposals would allow, does set out the project's total - and great - potential effects. And that information, plus the energy and economic factors involved, is being hotly debated in Maine and elsewhere. That is the sort of informed public assemssment that CEQ should promote, without imposing in advance the very judgements of values and policy that are at the heart of the fight.