Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Constance I. Millar; William B. Critchfield
    Date: 1988
    Source: Madroño Vol. 35(1): p. 39-53
    Publication Series: Miscellaneous Publication
    PDF: Download Publication  (575 KB)


    Crossing relationships were studies within and among the variable populations of Pinus muricata to test hypotheses about crossing barriers among certain populations. Crossability was assessed at the level of viable seed production following planned crosses. Populations north of Sea Ranch, Sonoma Co., California, crossed freely with parapatric but genetically distinct populations in central Sonoma Co., although some reduction in seed-set occurred in the F2 and backcrosses to F1. The distinctness of these adjacent poulations is most likely not maintained by post-pollination crossing barriers. Crossability of disjunct P. muricata populations generally decreased with distance between populations. populations north of Sea Ranch crossed freely with the Pt. Reyes poulation in Marin Co., less readily with the Monterey population, and not at all with the Purisima (southern California) or Baja California populations. Mainland and island P. muricata populations south of Monterey were highly interfertile. Test crosses were also attempted between P. muricata and the island populations of P. radiata,which have been considered closely related to southern P. muricata populations. Pinus muricata from Baja California did not cross, however, with either Guadalupe Island pine (P. radiata var. binata) or Cedros Island pine (P. radiata var. cedrosensis). Together with results from other crossing studies in the Californian closed-cone pines, the patterns of crossability indicate three crossing units in P. muricata: 1)northern P. muricata populations from Marin Co. northward, which are reproductively isolated from, 2)southern P. muricata populations including mainland and Channel Island populations from Purisima southward, and 3)Monterey P. muricata, which is intermediate between the first two units.

    Publication Notes

    • You may send email to to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Millar, Constance I.; Critchfield, William B. 1988. Crossability and relationships of Pinus muricata (Pinaceae). Madroño Vol. 35(1): p. 39-53

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page