
The Rare, Threatened, and Endangered Plants of California
Online Inventory version, from CNPS Inventory,
6th Edition, 2001
The heart of the CNPS Inventory is our assessment of
the current conservation status of each of our state's rare,
threatened, and endangered plants. We present these assessments
together with a summary of current information on the
distribution and ecology of each taxon. We also include entries
for plants that were considered but rejected for one or more
reasons, as well as other scientific names that have been used
in the standard literature or in previous editions of this Inventory.
Basis for Inclusion
The vast majority of the taxa in this Inventory are
vascular plants (ferns, fern allies, gymnosperms, and flowering
plants). With this edition, we for the first time also present
our evaluation of rarity and endangerment of California's
bryophytes (mosses, liverworts, and hornworts). Algae, fungi,
and lichens are not treated here.
A plant must be native to California to be included.
Ornamentals, plants escaped from cultivation, and naturalized
plants are excluded. So are the sporadic hybrids that sometimes
occur under natural conditions. The relatively trivial color
variants and occasional departures from typical vegetative or
floral conditions, referred to by botanists as
"forma," are similarly excluded.
This Inventory focuses on plants that are rare in
California. A very small number of plants that are still
somewhat common in California are included because they are in
decline and face further immediate threats. We recognize that
extensive habitat alteration and pervasive human impacts pose
serious threats to many other species that are still common.
However, evaluation of threats to species that are neither rare
nor imminently becoming so is outside the scope of this Inventory.
By limiting our scope in this way, we in no way imply that these
species are not of major concern.
Scientific Names
The plants in this Inventory are presented
alphabetically by their scientific names, the technical names
that have been properly published for them according to the International
Code of Botanical Nomenclature. See Shevock (1993) for a
general discussion of nomenclature.
In its simplest form, a scientific name has three parts. The
first is the genus or generic name. It is always capitalized.
The second part is the specific epithet, often incorrectly
called "the species name." Together, these two
components make up the species name. If a scientific name is
presented in its most complete form, these two words will be
followed by the names of one or more persons, often in an
abbreviated form, who first published the specific epithet or
subsequently published a taxonomic modification of the plant.
These names are the authorities. If a portion of an authority
occurs within parentheses, then the author in parentheses
originally placed the epithet in a different genus or species,
or once assigned it to a different taxonomic rank. The name
cited outside the parentheses is that of the person who
published the combination as it now appears.
Often the scientific name is more complex because botanists
have recognized categories below the level of species. The two
most useful are the subspecies (abbreviated ssp.) and the
variety (abbreviated var.) These names are also given according
the International Code and they have their own
authorities.
Consider the example Penstemon newberryi Gray var. sonomensis
(Greene) Jeps. Penstemon is the genus or generic name; newberryi
is the specific epithet; Gray, for Asa Gray, is the author of
the specific epithet; var. is the abbreviation for variety; sonomensis
is the subspecific epithet; (Greene), for Edward L. Greene,
first described the var. sonomensis as a full species;
and Jeps., for Willis Lynn Jepson, modified its taxonomic
position and made it a variety of P. newberryi. Following
the general practice for foreign words and phrases, Latin
portions of the name (genus, species, and infraspecific epithet)
are typically distinguished from surrounding text with
underlining or italic typeface.
Nomenclatural Usage
We use what we consider to be the current, best nomenclature
based on the recommendations of RPSAC and consultation with
taxonomic authorities. Many names in this Inventory have
been in use for a long time, appearing in Munz (1959, 1968,
1974) and Abrams (1923-1960). Others have been introduced or
reintroduced to us in The Jepson Manual (1993), or described new
to science in the last several years.
The usage in this Inventory does not follow any single
published source, though if other considerations are equal, we
follow usage in the current list maintained by The Jepson Manual
project. When the nomenclature we use varies from that of The
Jepson Manual, we include information in the Notes section of
each entry describing the situation. See Skinner and Ertter
(1993) for a discussion of taxonomic coordination between the Inventory
and The Jepson Manual.
Where there is disagreement among experts on taxonomic
distinctiveness, we lean toward recognizing doubtfully distinct
taxa. Such taxa are typically assigned to List 3. By encouraging
protection until taxonomic questions are resolved, we hope to
reduce ex post facto lamentation over taxa that have been shown
to be distinct only after their disappearance.
We do not include taxa that lack formally published
scientific names.
Common Names
Each of the plants also has a common or vernacular name
(except for the 28 nonvascular plants). We include these because
it is often easier for many of us to refer to a plant by a more
familiar sounding name. Of course, the majority of the plants in
this book have no real common names. Most of them were coined by
Leroy Abrams for his Illustrated Flora of the Pacific States. In
other instances, we simply followed his lead by contriving
names, usually by translating the Latin or Greek roots into
English or by selecting an appropriate geographical reference or
person's name. We have attempted to follow Kartesz and Thieret
(1991) in matters of capitalization, spelling, and hyphenation
of common names. Please see Appendix IV for an index between
common and scientific names.
Family Names
Each entry also includes the technical name of the family to
which the plant belongs. Note that all of these names end with
the suffix "-aceae." A few plant families have older,
alternative names that the International Code allows to
be used because their widespread acceptance predates formal
nomenclature. Gramineae is a perfectly acceptable alternative
for Poaceae; Compositae for Asteraceae; Cruciferae for
Brassicaceae; Umbelliferae for Apiaceae; Leguminosae for
Fabaceae; and Labiatae for Lamiaceae. However, these old names
are gradually losing favor, so we have used the standardized,
modern names for these families.
We have created five "lists" in an effort to
categorize degrees of concern. They are described as follows:
List 1A: Plants Presumed Extinct in California
The 29 plants of List 1A are presumed extinct because they
have not been seen or collected in the wild in California for
many years. Although most of them are restricted to California,
a few are found in other states as well. In many cases, repeated
attempts have been made to rediscover these plants by visiting
known historical locations. Even after such diligent searching,
we are constrained against saying that they are extinct, since
for most of them rediscovery remains a distinct possibility.
Note that care should be taken to distinguish between
"extinct" and "extirpated." A plant is
extirpated if it has been locally eliminated, but it may be
doing quite nicely elsewhere in its range.
We segregate these plants on their own list to highlight
their plight and encourage field work to relocate extant
populations. Since the publication of the fifth edition, eight
plants thought to be extinct in California have been
rediscovered. These are Ventura marsh milk-vetch (Astragalus
pycnostachyus var. lanosissimus), San Fernando Valley
spineflower (Chorizanthe parryi var. fernandina),
diamond-petaled California poppy (Eschscholzia rhombipetala),
Mojave tarplant (Hemizonia mohavensis), water howellia (Howellia
aquatilis), Howell's montia (Montia howellii),
northern adder's-tongue (Ophioglossum pusillum), and
Shasta orthocarpus (Orthocarpus pachystachyus). One
plant, frog's-bit buttercup (Ranunculus hydrocharioides),
was inadvertently placed on List 1A in the fifth edition and is
now correctly placed on List 2. Two plants that have not been
seen recently have been moved onto List 1A: Santa Barbara
morning-glory (Calystegia sepium ssp. binghamiae)
and mesquite neststraw (Stylocline sonorensis).
All of the plants constituting List 1A meet the definitions
of Sec. 1901, Chapter 10 (Native Plant Protection Act) or Secs.
2062 and 2067 (California Endangered Species Act) of the
California Department of Fish and Game Code, and are eligible
for state listing (see Conserving Plants with Laws and
Programs..., above). Should these taxa be rediscovered, it is
mandatory that they be fully considered during preparation of
environmental documents relating to the California Environmental
Quality Act (CEQA).
List 1B: Plants Rare, Threatened, or Endangered in
California and Elsewhere
The 1021 plants of List 1B are rare throughout their range.
All but a few are endemic to California. All of them are judged
to be vulnerable under present circumstances or to have a high
potential for becoming so because of their limited or vulnerable
habitat, their low numbers of individuals per population (even
though they may be wide ranging), or their limited number of
populations. Most of the plants of List 1B have declined
significantly over the last century.
All of the plants constituting List 1B meet the definitions
of Sec. 1901, Chapter 10 (Native Plant Protection Act) or Secs.
2062 and 2067 (California Endangered Species Act) of the
California Department of Fish and Game Code, and are eligible
for state listing. It is mandatory that they be fully considered
during preparation of environmental documents relating to CEQA.
List 2: Plants Rare, Threatened, or Endangered in
California, But More Common Elsewhere
Except for being common beyond the boundaries of California,
the 417 plants of List 2 would have appeared on List 1B. From
the federal perspective, plants common in other states or
countries are not eligible for consideration under the
provisions of the Endangered Species Act. Until 1979, a similar
policy was followed in California. However, after the passage of
the Native Plant Protection Act, plants were considered for
protection without regard to their distribution outside the
state.
With List 2, we recognize the importance of protecting the
geographic range of widespread species. In this way we protect
the diversity of our own state's flora and help maintain
evolutionary process and genetic diversity within species. All
of the plants constituting List 2 meet the definitions of Sec.
1901, Chapter 10 (Native Plant Protection Act) or Secs. 2062 and
2067 (California Endangered Species Act) of the California
Department of Fish and Game Code, and are eligible for state
listing. It is mandatory that they be fully considered during
preparation of environmental documents relating to CEQA.
List 3: Plants About Which We Need More Information - A
Review List
The 52 plants that comprise List 3 are united by one common
theme - we lack the necessary information to assign them to one
of the other lists or to reject them. Nearly all of the plants
remaining on List 3 are taxonomically problematic. For each List
3 plant we have provided the known information, indicated in the
Note where assistance is needed, and tentatively assigned the
taxon to a more definite list. Data regarding distribution,
endangerment, ecology, and taxonomic validity will be gratefully
received.
Some of the plants constituting List 3 meet the definitions
of Sec. 1901, Chapter 10 (Native Plant Protection Act) or Secs.
2062 and 2067 (California Endangered Species Act) of the
California Department of Fish and Game Code, and are eligible
for state listing. We strongly recommend that List 3 plants be
evaluated for consideration during preparation of environmental
documents relating to CEQA.
List 4: Plants of Limited Distribution - A Watch List
The 554 plants in this category are of limited distribution
or infrequent throughout a broader area in California, and their
vulnerability or susceptibility to threat appears relatively low
at this time. While we cannot call these plants "rare"
from a statewide perspective, they are uncommon enough that
their status should be monitored regularly. Should the degree of
endangerment or rarity of a List 4 plant change, we will
transfer it to a more appropriate list.
Very few of the plants constituting List 4 meet the
definitions of Sec. 1901, Chapter 10 (Native Plant Protection
Act) or Secs. 2062 and 2067 (California Endangered Species Act)
of the California Department of Fish and Game Code, and few, if
any, are eligible for state listing. Nevertheless, many of them
are significant locally, and we strongly recommend that List 4
plants be evaluated for consideration during preparation of
environmental documents relating to CEQA. This may be
particularly appropriate for the type locality of a List 4
plant, for populations at the periphery of a species' range or
in areas where the taxon is especially uncommon or has sustained
heavy losses, or for populations exhibiting unusual morphology
or occurring on unusual substrates.
CNPS R-E-D Code
With the five CNPS Lists we maintain a simple classification
that reflects an overall level of conservation concern. However,
rarity and endangerment are not strictly correlated, and our
approach to protecting plants that occur only in California is
somewhat different from our approach to protecting plants that
also occur elsewhere. Developing effective conservation
strategies requires that we distinguish among the separate
factors that contribute to our List assignments. These are:
rarity, which addresses numbers of individuals and distribution
within California; endangerment, which addresses the plant's
vulnerability to extinction for any reason; and distribution,
which describes the overall range of the plant. Together these
three elements form the R-E-D Code. Each element in the code is
divided into three classes or degrees of concern, represented by
the number 1, 2, or 3. In each case, higher numbers indicate
greater concern. The system is summarized as follows:
R - Rarity
1 - Rare, but found in sufficient numbers and distributed
widely enough that the potential for extinction is low at this
time
2 - Distributed in a limited number of occurrences,
occasionally more if each occurrence is small
3 - Distributed in one to several highly restricted
occurrences, or present in such small numbers that it is seldom
reported
E - Endangerment
1 - Not endangered
2 - Endangered in a portion of its range
3 - Endangered throughout its range
D - Distribution
1 - More or less widespread outside California
2 - Rare outside California
3 - Endemic to California
For example, an R-E-D Code of 3-3-3 indicates that the plant
in question is limited to one population or several restricted
ones, that it is endangered throughout its range, and that it is
endemic to California. A summary of the R-E-D code system
appears on the inside front cover for easy reference.
State and Federal Status
For each taxon with official status under the state and/or
Federal endangered species acts, the plant's status is
presented. Our definitions conform to those found in California
state law and federal regulations, described elsewhere in this
volume.
Distribution
The distribution of the taxon is described by county or
island within California, together with other states and
countries where we know the plant to exist. We record only
natural occurrences of rare plants, or occurrences that have
been reestablished within the species' historic range as part of
an approved recovery plan. For example, although both Northern
California black walnut (Juglans hindsii) and Monterey
pine (Pinus radiata) are widely planted within the state,
we track only the few natural occurrences of these taxa. When we
indicate that a particular plant occurs in a particular county,
we are making a positive statement that is based upon specimens,
photographs, the literature, or field observations. In no way
does this imply that a plant does not occur in other counties in
California or in other states. Our understanding of plant
distribution constantly improves, and new localities for rare
plants are frequently discovered, often in unpredicted
circumstances.
We use the symbols "*" and "?" as
modifiers, which respectively express extirpation and
uncertainty. They are also are explained on the inside front
cover for easy reference.
* extirpated
? uncertainty about distribution or identity
?* uncertainty about distribution, but extirpated if once
present
(*?) occurrence confirmed, but possibly extirpated
Quadrangles
To provide more detailed location information, we have also
cited the U.S. Geological Survey (USGS) 7.5 minute quadrangle
(quad) map for more than 1500 plants on CNPS Lists 1, 2, and 3.
We employ a modified version of the quad numbering system
previously used by the California Department of Water Resources.
Please see Appendix I to translate this system's quad numbers
into USGS topographic map names or vice versa. In those few
cases where a quad is listed without a letter following the
number, this indicates that our occurrence data are too vague to
pinpoint its location on a 7.5 minute quadrangle. As with
counties, this is positive siting information - when we indicate
that a plant has been reported from an area on a topographic
quad, it is based on hard data. In no way does this imply that a
plant does not occur on a topographic quad we have not listed;
rather, it may be there but botanists have yet to find it. As
with distribution, quads are also often modified with the
symbols "*" and "?", which respectively
express extirpation and uncertainty (see above).
Habitat Types
For each taxon, we present one or more habitats in which a
rare, threatened, or endangered plant is typically found. This
information is compiled from field survey forms, unpublished
reports, original descriptions, floras, and herbarium material.
Description of Habitat Types
Elevation
We present an elevational range for each taxon in meters. The
stated range is for the California portion of a plant's range
only (if the taxon also occurs outside the state). These
elevational range data have been accumulated from literature,
herbarium specimens, and field survey information.
Life Form
We provide a brief description of plant duration and life
form. The information was primarily developed from published and
unpublished literature and from herbarium material. Our
simplified classification system is as follows:
Duration: Annuals grow from seed and reproduce within
a single year. Perennials live more than one year.
Annual/Perennials are variable depending on environment and
conditions.
Growth Form: Herbs are herbaceous and lack
above-ground woody tissue. bulbiferous herbs have fleshy
underground storage organs typically derived from scale leaves
(this category includes cormiferous and other similar plants in
which storage organs have other origins). rhizomatous herbs have
underground stems (rhizomes), typically bearing shoots which
develop into new plants. stoloniferous herbs have above-ground
runners (stolons) which typically root and produce new plants.
Shrubs are smaller woody perennials that retain most of their
above-ground woody tissue and are typically many-stemmed. leaf
succulents have thick, fleshy leaves. stem succulents have
thick, fleshy stems and reduced or absent leaves.
Trees are larger woody perennials that retain all of their
above-ground wood tissue and are typically single-stemmed.
Vines are twining woody perennials requiring external support
for growth.
Mosses are small green plants (one of three groups of
bryophytes) with structures that resemble miniature leaves and
stems. The leaves generally have a midrib called a costa. The
sporophyte (the spore-bearing structure) is persistent for
weeks.
Liverworts are small green plants (one of three groups of
bryophytes). There are both leafy and thalloid types - leafy
liverworts lack a midrib on the leaves, while thalloid
liverworts have no leaves. The sporophyte is short-lived.
Leaf Condition (for shrubs, trees, vines only):
Deciduous plants shed their leaves for part of the year.
Evergreen plants retain their leaves for an entire year.
Special Habitat: Aquatic plants are submerged or
floating on the water surface. Emergent plants are rooted in
water but bear some foliage out of the water.
Mode of Nutrition: Achlorophyllous plants lack
chlorophyll and live on existing organic matter in the soil.
Hemiparasitic plants are connected to host plants and derive
energy, water, and minerals from them, but also maintain their
own functional root systems or photosynthetic surfaces.
Parasitic plants are connected to host plants and rely solely on
them for energy, water, and nutritional requirements.
Carnivorous plants trap insects and other small animals and
derive nourishment from them.
As in most classifications, some of the above distinctions
are somewhat arbitrary, particularly the divisions between
growth forms. Furthermore, plant growth form can vary depending
on geography and local environmental conditions. Perennials that
are often referred to as either suffrutescent herbs or subshrubs
present special difficulties. Generally, if these plants die
back seasonally to the ground or to a small crown of woody
tissue we classified them as herbs, and if they retain much or
all of their woody above-ground tissue we called them shrubs.
Blooming Period
We show the months when each rare plant is typically in
bloom. For ferns and other spore-bearing plants, we have given
the months when spores are released and spore-bearing structures
such as sori are typically present on the plant. We have not
included any comparable information for gymnosperms and
nonvascular taxa.
Notes
Many entries include additional notes on distribution,
endangerment, relationship to names in The Jepson Manual, or
important literature citations. We have again included
information about legal status and endangerment in neighboring
states in the notes; official state designations are
specifically indicated as such and capitalized, as in
"State-listed as Endangered in OR". We have made a
special effort to indicate missing information about
distribution, endangerment, or taxonomy for each entry, in the
hope that knowledgeable users will fill in the gaps.
Abbreviations that are commonly used in the notes are explained
on the inside front cover.
Literature Cited
Abrams, L.R. 1923?1960. An Illustrated Flora of the Pacific
States, Washington, Oregon and California. Vol. 4 by R. Ferris.
Stanford University Press. Stanford, CA. 4 vols.
Hickman, J.C., ed. 1993. The Jepson Manual: Higher Plants of
California. University of California Press. Berkeley, CA. 1400
pp.
Holland, R.F. 1986. Preliminary Descriptions of the
Terrestrial Natural Communities of California. Nongame-Heritage
Program, California Department of Fish and Game. Sacramento, CA.
156 pp.
Kartesz, J.T., and J.W. Thieret. 1991. Common names for
vascular plants: Guidelines for use and application. Sida
14(3):421-434.
Munz, P.A. 1959. A California Flora. In collaboration with
D.D. Keck. University of California Press. Berkeley, CA. 1681
pp.
Munz, P.A. 1968. Supplement to a California Flora. University
of California Press. Berkeley, CA. 224 pp.
Munz, P.A. 1974. A Flora of Southern California. University
of California Press. Berkeley, CA. 1086 pp.
Shevock, James R. 1993. How plants get their names and why
names change. Fremontia 21(1):19-24.
Skinner, Mark W. and Barbara Ertter. 1993. Whither rare
plants in The Jepson Manual? Fremontia 21(3):23-27.

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