Taxonomic Novelties from North America north of Mexico:
A 20-Year Vascular Plant Diversity Baseline
Ronald L. Hartman and B. E. Nelson
Hartman, R. L. and B. E. Nelson. 1998. Taxonomic novelties from North America north of Mexico: A 20-year vascular plant diversity baseline. Monogr. Syst. Bot. Missouri Botanical Garden 67: 1-59.
A survey of the literature and the Gray Herbarium Card and Kew indices was performed to determine the number of taxa new to science published in North America north of Mexico from 1975 through 1994. A total of 99 families were represented, although 34 contained 1025 taxa (85.9% of the total). Five genera, Apacheria, Cochiseia, Dedeckera, Shoshonea, and Yermo, and one nothogenus, xDryostichum, were based solely on newly described species. New species and terminal infraspecific taxa were distributed as follows: pteridophytes with 78 (6.5%), gymnosperms with 6 (0.5%), and angiosperms with 1113 (93%) for a sum of 1197 (59.85 taxa or 27.9 species per year). During this 20-year period, the five-year averages for the publication of new species were 28, 35.6, 26.2, and 30.8. Comparable averages for subspecies and varieties were 7.8 and 14.8; 7 and 16; 5.8 and 17; 7.2 and 14.8, respectively. The total number of new subspecies proposed as terminal taxa was 139 (30.7%), compared to 313 (69.3%) for varieties. Data on species for the period 1955 through 1974 are also provided (32.1 species per year). With the exception of the years 1971 through 1974, when more new species were proposed, the frequency of taxonomic novelties is relatively constant over the 40-year (30 species per year). A total of 505 authors participated in the publication of the 1197 new taxa, although 11.8 percent of them authored 703 taxa (59% of total). Ninety-one books and journals were involved, although 36 served as the outlet for 1093 novelties. The new taxa were divided among the following categories of study: floristics, 375 taxa; plants of conservation concern, 33; taxonomy, 703; and biosystematics, 86. The states yielding the greatest number of holotypes were: California, 217; Utah, 183; Texas, 70; Nevada, 63; Arizona, 57; Oregon, 42; New Mexico, 41; Florida, 38; Idaho, 33; Wyoming, 32, <Colorado, 29, . . . Washington, 13, Montana, 12; British Columbia, 9, and Alberta, 3 (Rocky Mountain political entities in bold). Likewise, the leading floristic areas, based on holotypes, were Intermountain, 287; California, 217; Rocky Mountain, 131; Southeast, 113; Southwest, 107, Texas, 70, Canada, 62, Northwest, 64, and Northeast 51. It is concluded that the resurgence of biodiversity studies, as well as the efforts of monographers and contributors to regional floristic projects and to Flora of North America (FNA), will help maintain the current level of publication of novelties, but that within the next 10 to 15 years the discovery of previously unknown taxa is likely to decrease.
Stated differently, this is both a reflection of the amount of floristic and taxonomic work being done by state or region as well as the amount of continued investigatioon warranted. A more extensive discussion of floristic surprises in North America and a review of the justification for floristic research may be found in Ertter (2000).
Ertter, B. 2000. Floristic surprises in North America north of Mexico. Ann. Missouri Bot. Garden. 87: 81--109.