In the UK we have a system of "County Recorders" who take resonsability for recording the flora in their areas. This includes garden escapes, invasive species, rare natives and so on. The information is then compiled on a national basis. Obviously the quality of the records depends on the time and the expertise that a recorder can give to the task but overall there is a fairly complete published record. again on the subject of invasive plants, other areas of the world might be more vulnerable to invasive species but Britain is perhaps in an unusual position in having a very high proportion of its plant species introduced, due to being a island, and due to the last Iceage, and due to having a climate suitable for cultivating such a wide range of plants. Rhododendron ponticum is much hated as a forigen invasive, In large areas of the UK it performs as a primary coloniser, but when it gets rust, or breaks as the branches get big, or because of snow, birch and holly get in. It may be 100 years before the birch gets a grip or the holly starts to shade out the Rhododendron, and Oak gets in to start woodland regeneration. unfortunately the conservationists dont think in terms of an evolutionary time scale 30 years ago everyone was hacking down sycamore as a forigen invasive, (I'm not sure but I believe it was here pre Iceage). In any case its sugary sap provides for a wide range of insect life and the food chains suported by them. Now it is fasionable to bash Himalayan balsam, (Impatiens glandulifera). Yes it is invasive, but it is late up and its sites provide cover among the detritus for a lot of native insects and small mammals, frogs, birds and so on as well as a protection for earlier flowering/ growing smaller plants grasses, arable weeds/ annuals, bulbs and so on. Peter (UK) I On Sat, Sep 10, 2011 at 5:24 AM, Michael Mace <michaelcmace@gmail.com>wrote: > ...based on the assumption that there is a large supply > of attractive ornamental plants outside the US that, if imported, could > become an invasive threat. > > So there's a lesson here for the record-keepers in the federal government. > I've communicated with them about it, and the dialog has been very positive > (thanks to Bill Aley for setting that up). > > But I think there's a deeper lesson that we all need to absorb: Any plant > species that's attractive enough that someone introduced it into Australia > or the UK or some other part of Europe is also attractive enough that > people > have brought it into the US, repeatedly and enthusiastically, for many > decades. > > So at least in the US, the issue isn't really about guarding the borders; > it's mostly about assessing the invasiveness of things already here, making > sure they are grown responsibly, and flagging the genuinely dangerous > > Mike > San Jose, CA > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >