COLLECTING and cataloging of plants native to North America began in the late 17th century, but the first truly exhaustive listing of the continent's plant life - everything from giant redwoods to lowly mosses - is only happening now. The first two volumes of the 14-volume ``Flora of North America'' (Oxford University Press, $75 per book) appeared this fall.
The project had started and stalled a number of times in the past, says Nancy Morin, assistant director of the Missouri Botanical Garden in St. Louis. She is the convening editor of the ``flora,'' the term used for a systematic listing of the plants found in a region.
Dr. Morin says that Harvard University botanist Asa Gray attempted to list all the plants of North America in the 19th century, when the field work and collecting was ``hot and heavy.'' Professor Gray and his colleagues became overwhelmed by the task, she says. The cataloging work instead shifted toward more easily contained regional and state floras.
Then in 1965, botanists in the United States realized that their colleagues in Europe and the Soviet Union were plunging ahead with the task of cataloging the plants of their regions.
``Why not us?'' the Americans asked themselves. A committee was organized and some funding was lined up, but the effort tailed off in a few years and was suspended in 1972.
Couldn't the various regional floras have been pieced into a work on the whole continent? Those volumes talked about ``different kinds of things,'' explains Morin. Without an overall work consistently organized, ``you can't really get the picture of a particular group of plants as it occurs throughout the continent,'' she says.
And such a work is of more than scholarly interest. A variety of specialists - foresters, conservationists, agricultural researchers, and pharmacists, to name a few - will put the new flora to immediate use.
People interested in protecting endangered plants will have at their fingertips a thorough discussion of each species' range and the history of its discovery. Pharmaceutical companies that have found interesting chemical compounds in one species will be able to quickly identify related plants for further research.
Chris Topik, botany program leader at the US Forest Service in Washington, says the new flora will be invaluable as ``a central authoritative source'' on the range and distribution of plant species.
A single comprehensive guide will clear up ambiguities, he adds, ``so we all call the same species by the same name.'' The Forest Service has already purchased numerous copies of the first two volumes. Mr. Topik describes how Volume 2 helped him get immediate data on the Port Orford cedar, a tree native to the southern Oregon and northern California coasts that has a restricted range and needs protection.
The revived flora effort dates from 1982, when a number of botanists decided to give the project ``another shot,'' as Morin puts it. The Missouri Botanical Garden, one of the largest outposts of botanical research in the world, was chosen as the organizational center.
This time, the work seemed to have plenty of momentum, says Morin. Heightened interest in biological diversity and environmental protection helped, as have such related projects as the biological survey of the US recently initiated by Interior Secretary Bruce Babbitt.
``Our kind of work provides a base line for all kinds of activities,'' says Morin.
The flora project has stimulated some fresh field work by botanists who are contributing research articles to the 14-volume text. And some new discoveries are being made, says Morin.
She notes that the section on ferns will include 70 species that either have new names or are new entries since the last thorough treatment of the subject came out 10 years ago.
``The thing people find most frustrating,'' she adds, ``is that a lot of intensive research is going on right now.'' But in order to get the volumes in print, the editors have to cut off the addition of new material at some point. So to a lot of botanists the flora will be ``just a status report,'' says Morin, but it will nonetheless be of great value to its users.
The first volume of the series gives background on climate, soils, topography, and other elements that determine the types and ranges of plant life. The second volume concentrates on gymnosperms - such as conifers. The third through 12th will deal with flowering plants.
The last two will be mosses and liverworts, and a fina cumulative index to the whole thing.
The organizational scheme is according to related plant families, not the alphabet.
The books will be coming out every two or three years, sometimes two a year, until 2002. Four-hundred scholars, from every state and Canada, are involved. The flora also embraces Greenland, since its plant life is closely related to Canada's. It doesn't include Mexico because that country's botanists have their own listing project underway - and also, says Morin, because Mexico's huge variety of vegetation would have almost doubled the size of the flora.
As it is, the volumes will include about 22,000 plant varieties. Hawaii is also excluded, since its plants belong in a Pacific flora, not a North American one.
Foundation grants have contributed about $400,000 a year to the flora project, and Morin calculates that various institutions have donated at least another $500,000 a year in time and talents. ``Flora of North America'' will have an on-line edition, too. All the textual material will be available on a data base, says Morin, and work is progressing to include the maps and charts as well.
Exhaustive floras already exist for some parts of the world, such as Europe, sections of Russia, and Central America. A revised flora of China is underway, with much of the work coordinated by the Missouri Botanical Garden.
But there are ``major gaps,'' says Morin. Much is known about Africa's native plants, but the resources to put together a systematic catalog of them haven't been mustered.
Too little is known about the plants of Indonesia, Malaysia, and much of South America to justify a flora for those areas. In those regions, the botanists' work of collecting, analyzing, and listing is about where the North American project was a century ago.