Flora of North America North of Mexico: Pteridophytes and Gymnosperms (Flora of North America: North of Mexico)

Rating:
Summary: A variable book with some very good and other poor parts
Review: This review is only about the conifers section of the Flora. Coverage of the conifers is complete for North American species, with a few naturalised exotics as well, but by no means all of these, e.g. Pinus halepensis naturalised in California is not in. The classification follows the most recent evidence, including the submergence of Taxodiaceae in Cupressaceae for which acceptance is becoming wider. Each genus has been authored separately, and inevitably the content varies according to the author. Some are very good, while others, notably Pinus, are much poorer.

Abies, compiled by R S Hunt, a long-time authority on silver firs, is the only genus in which readers might find any unfamiliar names. Hunt has found distinct differences between coastal and inland populations of Abies lasiocarpa, and separates the inland ones as a distinct species Abies bifolia. Also split off is the Sierra Nevada White Fir, usually treated as a variety of the Colorado White Fir but here a species Abies lowiana. He demonstrates good grounds for treating them as more than varieties; in other parts of the world they might have been treated as subspecies, but this rank appears to have been actively discouraged by the editors of the Flora.

Tsuga and Picea are both by R J Taylor, who like Hunt is an acknowledged authority on his genera, and both are covered well. Inevitably, there are a few small errors in some of the measurements: Picea sitchensis is given a maximum height of 80m, though it is known to grow to 96m, while Picea engelmannii is given 60m, though the tallest I can find published data for is 55m.

Pinus receives the poorest treatment of any of the genera. It is by R Kral, an unfamiliar name in conifer taxonomic circles who has no work cited in Farjon's 1990 Bibliography of Conifers. Kral corsorily dismisses or does not even mention several well-founded taxa, notably among the pinyons. He also does not appear to understand the tenet in the International Code for Botanical Nomenclature that subspecies is a higher rank than variety, as he gives the large differences in Pinus contorta recognition only at varietal rank, while giving the very small differences between the two populations of Pinus torreyana subspecies rank. Had this genus been covered by almost any other American pine specialist - e.g. Lanner, Malusa or Haller - a much better account would have resulted

Distribution maps are given for all species, but are very small and not too clear for species with small ranges like Cupressus macrocarpa; for these, just the state or province where it occurs should have been shown, not the whole continent.

Keys are given for all genera with more than two taxa. Like the texts they vary, some are easy to use with that for Picea the best among the larger genera. The key for Pinus includes (lead 28) the inexcusable cop-out "pines of eastern North America / pines of Western North America". This makes it unusable not only for anyone dealing with cultivated or naturalised plants, but also anywhere where trees might possibly be planted or naturalised - thus including all managed forests, in effect all trees outside of National Parks and nature reserves and perhaps even some in these. Some of the keys also seem to assume that you carry a powerful microscope and portable laboratory wherever you go, citing differences in resin canal position or pollen size, though these are usually only as supplementary features.

The editing and proof-reading has been done well, and it is refreshing to see an American text using international metric measurements, not archaic feet and inches. It is also very pleasantly free of misprints and other such errors. The only one I found is the vernacular name for Scots Pine (Pinus sylvestris), mis-spelled 'Scotch', thereby making it a whisky, not a tree!