Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support

Major Disjunctions in the Geographic Ranges of Seed Plants

Robert F. Thorne
The Quarterly Review of Biology
Vol. 47, No. 4 (Dec., 1972), pp. 365-411
Stable URL: http://www.jstor.org/stable/2820737
Page Count: 47
  • Read Online (Free)
  • Download ($19.00)
  • Cite this Item
If you need an accessible version of this item please contact JSTOR User Support
Major Disjunctions in the Geographic Ranges of Seed Plants
Preview not available

Abstract

In attempting to review and classify the major intercontinental disjunctions in the geographic ranges of seed plants, six guiding principles are followed where possible. Sixteen categories and 34 subcategories of disjuct ranges of intercontinental magnitude (Table 1) are classified according to continents and latitudinal bands involved. Widely distributed taxa are, by their very nature, disjunct; they are therefore classified along with the more traditionally discontinuous types. Thus, for the most part, only endemics and taxa with smaller intracontinental disjunctions are omitted from this review. Generalized distribution maps are presented for selected taxa characteristic of each of the dicontinuous types. Other taxa are listed for each of the categories and subcategories, and compendia of good distribution maps are cited for ready reference to additional examples. Possible explanations for the major discontinuities are discussed. Finally, a statistical summary is given of the numbers of disjunct taxa and the largest disjunct categories. Among the Angiospermae (the flowering plants), approximately 78 per cent of the 324 families, 24 per cent of the genera, and 1 per cent of the species are widely disjunct. The largest number of disjunct genera are found among the African-Eurasian-(Pacific) (600), Asian-Pacific (460), Pacific (370), North American-South American (ca. 360), Pantropical (334), North Temperate (316), and Subcosmopolitan (125) categories; the largest number of disjunct families among the Subcosmopolitan (90), Pantropical (59), North Temperate (20), African-Eurasian (Pacific) (17), and North American-South American (13) categories.

Page Thumbnails

  • Thumbnail: Page 
365
    365
  • Thumbnail: Page 
366
    366
  • Thumbnail: Page 
367
    367
  • Thumbnail: Page 
368
    368
  • Thumbnail: Page 
369
    369
  • Thumbnail: Page 
370
    370
  • Thumbnail: Page 
371
    371
  • Thumbnail: Page 
372
    372
  • Thumbnail: Page 
373
    373
  • Thumbnail: Page 
374
    374
  • Thumbnail: Page 
375
    375
  • Thumbnail: Page 
376
    376
  • Thumbnail: Page 
377
    377
  • Thumbnail: Page 
378
    378
  • Thumbnail: Page 
379
    379
  • Thumbnail: Page 
380
    380
  • Thumbnail: Page 
381
    381
  • Thumbnail: Page 
382
    382
  • Thumbnail: Page 
383
    383
  • Thumbnail: Page 
384
    384
  • Thumbnail: Page 
385
    385
  • Thumbnail: Page 
386
    386
  • Thumbnail: Page 
387
    387
  • Thumbnail: Page 
388
    388
  • Thumbnail: Page 
389
    389
  • Thumbnail: Page 
390
    390
  • Thumbnail: Page 
391
    391
  • Thumbnail: Page 
392
    392
  • Thumbnail: Page 
393
    393
  • Thumbnail: Page 
394
    394
  • Thumbnail: Page 
395
    395
  • Thumbnail: Page 
396
    396
  • Thumbnail: Page 
397
    397
  • Thumbnail: Page 
398
    398
  • Thumbnail: Page 
399
    399
  • Thumbnail: Page 
400
    400
  • Thumbnail: Page 
401
    401
  • Thumbnail: Page 
402
    402
  • Thumbnail: Page 
403
    403
  • Thumbnail: Page 
404
    404
  • Thumbnail: Page 
405
    405
  • Thumbnail: Page 
406
    406
  • Thumbnail: Page 
407
    407
  • Thumbnail: Page 
408
    408
  • Thumbnail: Page 
409
    409
  • Thumbnail: Page 
410
    410
  • Thumbnail: Page 
411
    411