Here you go Adam, from invasivespeciesinfo.gov. There are various definitions and some states have lists of plants that persist as "invasive" and others have true invasives. Overall the number of actual "invasives" is relatively limited.
Section 1. Definitions.
(a)
"Alien species" means, with respect to a particular ecosystem, any
species, including its seeds, eggs, spores, or other biological
material capable of propagating that species, that is not native to
that ecosystem.
(b) "Control" means, as appropriate,
eradicating, suppressing, reducing, or managing invasive species
populations, preventing spread of invasive species from areas where
they are present, and taking steps such as restoration of native
species and habitats to reduce the effects of invasive species and to
prevent further invasions.
(c) "Ecosystem" means the complex of a community of organisms and its environment.
(d)
"Federal agency" means an executive department or agency, but does not
include independent establishments as defined by 5 U.S.C. 104.
(e) "Introduction" means the intentional or unintentional escape,
release, dissemination, or placement of a species into an ecosystem as
a result of human activity.
(f) "Invasive species"
means an alien species whose introduction does or is likely to cause
economic or environmental harm or harm to human health.
(g)
"Native species" means, with respect to a particular ecosystem, a
species that, other than as a result of an introduction, historically
occurred or currently occurs in that ecosystem.
(h)
"Species" means a group of organisms all of which have a high degree of
physical and genetic similarity, generally interbreed only among
themselves, and show persistent differences from members of allied
groups of organisms.
(i) "Stakeholders" means, but
is not limited to, State, tribal, and local government agencies,
academic institutions, the scientific community, nongovernmental
entities including environmental, agricultural, and conservation
organizations, trade groups, commercial interests, and private
landowners.
(j) "United States" means the 50 States,
the District of Columbia, Puerto Rico, Guam, and all possessions,
territories, and the territorial sea of the United States.
--- On Thu, 4/8/10, Adam Fikso <adam14113@ameritech.net> wrote:
From: Adam Fikso <adam14113@ameritech.net>
Subject: Re: [pbs] "invasive"
To: "Pacific Bulb Society" <pbs@lists.ibiblio.org>
Date: Thursday, April 8, 2010, 5:57 AM
How about "liberally encroaching?
., And re the definition, Boyce-- can you specify the legal parameters so we can learn how not to use the term?