ANF Introduction

This flora is an account of all species of vascular plants known to inhabit, currently or in the recorded past, wildlands and disturbed habitats of the Santa Monica Mountains (SMM) and adjacent Simi Hills (SH) of southern California.

The Santa Monica Mountains extend from Griffith Park and the Hollywood Hills in Los Angeles County, skirted by the Los Angeles River on the north, westward to Calleguas Creek bordering Camarillo (77 km), and then south to the Pacific Ocean at the Point Mugu Naval Air Station in Ventura County.  The mountains create the uphill southern edge of the San Fernando Valley, from Burbank through Woodland Hills and then parallel with the Ventura Freeway (Highway 101) westward through the Conejo Grade.  Among many communities included within the mountain range are ones like Brentwood, Bel Air, Beverly Hills, Hollywood, Pacific Palisades, Malibu, Topanga, Calabasas, Agoura Hills, Westlake Village, and Thousand Oaks.  We have defined the boundary for the flora so that it excludes densely populated flat areas of the city of Santa Monica and of the San Fernando Valley.

The Simi Hills extend from northern Chatsworth in Los Angeles County westward to where they contact the Santa Monica Mountains at Arroyo Canyon near Thousand Oaks and Newbury Park in Ventura County.  Generally speaking the Simi Hills are north of the Ventura Freeway, and the Santa Monica Mountains are south of it, although the city of Thousand Oaks is part of both formations.  Communities included in the Simi Hills, at least in part, are Chatsworth, Chatsworth Manor Lake, the fringes of West Hills, Hidden Hills, the southern fringes of the city of Simi Hills, and the undeveloped slopes of Oak Park, Thousand Oaks, and Newbury Park.

The current visitors center (2012) of the Santa Monica Mountains National Recreation Area (SMMNRA), located in Thousand Oaks, is in the Simi Hills, and those park facilities will be transferred to SMMNRA King Gillette Ranch, which is in the heart of the Santa Monica Mountains.  Within the boundaries of the flora are notable cultural centers and landmarks, including the Getty Center, the Los Angeles Zoo, Griffith Observatory, Pepperdine University, the Hollywood sign, the Ronald Reagan Presidential Library, and several of the most famous beaches in North America.   The area under study is approximately 1180 square kilometers, from which must be subtracted greater than 200 square kilometers of fully suburbanized neighborhoods.  For example, the acreage of chartable wildland in SMM is currently around 150,000 acres (ca. 61,500 hectares), which of course will be diminished with new construction.

The range has a Mediterranean-type climate, which is characterized by having a mild winter with a somewhat predictable rainy season from December through March or April from Pacific storms, and dry, moderately hot May through October, typically with little or no measurable rainfall.  Local freezing is occasional but of short duration, never lasting more than twelve hours, and snow is a rare event.

The dominant, characteristic vegetation of this zone is chaparral, and in range approximately two-thirds of the wildlands are covered with some form of chaparral, which can be impacted by cold temperatures (Davis, 2007).  On the drier, lower elevations and drier slopes occur forms of coastal sage scrub.  Natural vegetation is narrowly dissected by tree-dominated southern oak woodland and riparian woodland, wherever moisture is more abundant, e.g., along canyon bottoms and creeks.  The grasslands, with and without oaks, that occur in range have been greatly altered, especially by the invasion of alien plant species, grazing pressures by domesticated livestock, and reactions to the intensity and frequency of fires (Heady, 1979; Keeley).    Along the coastline are found strand plant communities growing on sand dunes, coastal salt marsh at Mugu Lagoon and the mouth of Malibu Creek, and bluff scrub, all influenced by the moderated maritime conditions, including milder temperatures and occurrence of fog potentially any day of the year.  Morning or late-day fog in any season is fairly common for the coastal canyons of the Santa Monica Mountains.

The first comprehensive floristic treatment of the Santa Monica Mountains was coauthored by UCLA alumnus Peter H. Raven and UCLA professor Henry J. Thompson and published through the UCLA Herbarium in 1966.  Flora of the Santa Monica Mountains, California was a simple and inexpensive manual with keys to identify 820 native and naturalized species, and it included only highly abbreviated species descriptions and minimal illustrations.  The 1966 flora became a popular manual that was used in introductory plant taxonomy classes of area colleges and universities and by local amateur and professional botanists.  Having a local flora meant that classes could avoid using the more expensive and inclusive flora of California (Munz and Keck, 1959; Munz, 1963), covering more than 6400 species, and most names adopted in the local flora were those used in the state flora.  To illustrate changes in our understanding, the recently published flora of California, The Jepson Manual (Baldwin et al., 2012), recognizes 7840 taxa of native, naturalized, and waif plants, many of which have had significant alterations in their scientific names and authorities from how they were treated in 1966.

A Naturalist’s Flora of the Santa Monica Mountains and Simi Hills, California is the third revision.  In 1977, the SMM flora was revised by David S. Verity, senior museum scientist at the UCLA Herbarium bringing scientific nomenclature up-to-date, to be consistent with names and authorities recognized in A Flora of Southern California (Munz, 1974).  The second edition of the SMM flora (Raven, Thompson, and Prigge, 1986) was greatly expanded and had significant changes, including 72 additional species that had been verified from the SMM, increasing the total to 880 taxa, of which 644 were natives.  Copies of the second edition were sold and distributed through Southern California Botanists.  The current, two-volume revision is massive because boundaries were modified to exclude urbanized regions but include the Simi Hills, and overall added many species discovered in nature or from professional records, raising the current total to about 1100 taxa, still roughly one-seventh of the vascular plant taxa in California (Baldwin et al., 2012).  Adding the Simi Hills increased area of the range by 30% and was important for managers of local parks and naturalists while increasing taxa by less than 5%.

A Naturalist’s Flora bears little resemblance to earlier versions in that it has attempted to provide complete descriptions of every species, i.e., it is a primary resource so that the user generally will not need to consult other books for descriptions.  The current revision no longer includes reviews and analyses of plant communities, physiognomy, geology, and climate, leaving that for a different venue, so that the only the goal is to produce a reference having complete descriptions of the plants and tools with which to identify them with confidence.


To determine the identity of a particular plant, plant taxonomists have for several generations used keys.  A key consists of a series of paired statements (couplets) that are mutually exclusive, so that the observer must answer whether the plant under consideration fits one statement or the alternative statement of a couplet.  By answering yes or no to each statement and progressing through a series of sequential (numbered or lettered) couplets, with keying the observer eventually arrives at a solution.  Then the plant must be compared with the description and images or museum specimens (herbarium vouchers) to determine whether the identification is correct.  The key therefore “unlocks” the name of a plant.

Errors in judgment by the observer for any couplet will lead to a misidentification, but also authors who write keys may have included an error in a couplet, such as a wrong measurement or shape, which can inadvertently lead to misidentification.  Errors in judgment are often due either to what is the true nature of the structure discussed, which the naïve observer may not understand, or about what specifically the author of the key statement is asking.  Errors in writing keys result when authors do not use features and traits (characters and characteristics) that are absolutely correct for every species included, which can therefore cause the observer to reject a statement and follow a wrong path through the numbered couplets.  When the observer must answer both statements of a couplet yes or alternatively no, the method reaches a roadblock and must be abandoned, or restarted to determine where a wrong choice was  previously made.

Keying is an iterative process.  The skill of someone keying is arriving at the correct identification time after time, and that in large part reflects excellent understanding and interpretation of the features in keys and, realistically, how many times the observer has used the device and knows how to maneuver smoothly through the couplets while ignoring solutions that are obviously wrong.  With years of experience and knowing thousands of plants by sight, even a professional can experience difficulties in keying.  Difficulty occurs when the author of a key is too vague about characters, so that a clear choice cannot be made for a couplet because the statements are not mutually exclusive, e.g., size range of blades or petals is overlapping enough to raise some confusion.  Second, experts will use special terms for features of their group, a trait which may be unfamiliar to those trained in other groups.  Third, experts tend to require for proper identification interpreting a structure that may or may not be present on the specimen in hand, e.g., mature fruits or features that are short-lived (basal leaves, stipules, bracts, etc.), so that a couplet cannot be successfully judged.

Ideally, a key for plants should be strictly dichotomous, meaning that every portion in a statement should have its opposite in the alternative statement, e.g., petals are yellow versus they are purple, or blades are hairy versus glabrous (completely hairless).  Dichotomous keys have many advocates, but authors depart somewhat from the ideal wherever the plants do not conveniently fit into sharply defined categories, where there is a considerable amount of variability, and wherever including some information in a statement helps the observer overcome hesitation for that statement being the correct choice.  For example, it is helpful to know that a plant grows in a salt marsh, i.e., some highly specialized or derived features that would cinch identification for that plant, all other things being correct.

In this treatment we have done several things that should assist the amateur in keying, but likely will upset some professionals.  First, for each couplet we have attempted to include features about something vegetative, something about the flowers, and something about the fruits, so that a plant can potentially be identified nearly any time you find it during the growing season.  This should eliminate some frustration, e.g., that mature fruits must be present.  Second, we have tried not to use features that would do the plants harm, e.g., belowground parts that would have to be removed from the soil to answer a couplet.  That seems a wise strategy to avoid problems of removing plants of conservation interest, especially when the observer would not a priori know its status.  Third, we have tried to emphasize features that can be observed without having to resort to high magnification and critical, technical analysis (testing with chemicals or studying chromosomes), although those features can be remarkably reliable.  Fourth, we have declined using certain features that experts have relied on traditionally for identification; we instead shifted attention for our local plants to features that are convenient and reliable features that “work” for this particular flora.

Keys included in this flora are those to determine the broad group to which a vascular plant belongs (angiosperm, gymnosperm, and plants that never form seeds), then to identify family, genus, species, and variety or subspecies.  There are of course obvious limitations to identification already when a plant in hand may not have seeds or other reproductive structures, so that status cannot be determined, but most amateurs and professors have a hunch on plant affiliation in cases where seeds are not present, i.e., the plant is a fern or a dicotyledon.  There are certain plants, especially aquatic ones, which are never found with reproductive features, so they must be keyed out using only vegetative features.

If a plant keys easily to a particular family or genus but then not to genus or species, the observer has several things to consider.  It may be a plant that was overlooked by the authors of this flora and should be considered as an addition to the flora.  It may be a plant that was intentionally not included because it was not considered to be reproducing on its own.  Or it may be that the key has some error that should be corrected.  To benefit the plant community, any of these should be reported to a park service professional to pursue.  There are notes on certain species that have been excluded for the time being in this flora but should be expected or given additional consideration.

Using fresh materials

A deliberate attempt was made to write technical descriptions from living materials collected within the range.  We anticipated that most users of this flora will be college students, amateur and professional naturalists, and environmental consultants trying to identify specimens in habitat or from freshly collected plant parts.  This approach is not practiced, or practical, for larger floras, wherein most specimens used in descriptions are dried herbarium materials, often collected decades earlier.  If materials are dried, it may be easier to use keys in The Jepson Manual (Baldwin et al., 2012).  Our descriptions, with several exceptions, are newly researched, full descriptions rather than copies of existing descriptions, so there will be discrepancies when comparisons are made to briefer or more superficial descriptions, as well as those based on materials also occurring outside the range.  Care was taken to observe local variability of many species, although that task is impossible to complete for every species, at least in a reasonable time frame.  Descriptions were researched with only local features and values recorded, not those throughout its entire state or world distribution.

Benefits of utilizing fresh materials are numerous.  Natural colors can and should be expressed in a more precise fashion. While researching local plants in fresh condition, a conscientious effort can be made to find a wider range of variability than is ever represented on herbarium sheets.  Many characteristics of fresh plants disappear or become inconspicuous upon drying.  Because plant organs often shrink and shrivel when dried, using only herbarium specimens can also lead to underestimating normal sizes of delicate structures.  We sampled variability seen locally, rather than being concerned about variability for all California populations.  Therefore, our descriptions may not capture all statewide variation observed within each taxon, but for that information the larger regional floras can be consulted.  The flip side is that regional floras should be rewritten to represent better populations of southern California.

In pursuing our policy of relying on living materials, we found a very large number of quantitative and qualitative disagreements with the conventional treatments covering many additional species.  Our populations undoubtedly also show local genotypic and phenotypic differences not noted by authorities, whom often have never examined materials from our populations.  We have been diligent to at least double check measurements from fresh materials to insure accuracy, while verifying the ranges of characters using herbarium materials collected from local sites.

Other characteristics of this revision are worth mentioning

(1) Every description is stand-alone, for each species, subspecies, or variety, so that the user will not have to flip back and forth from species description to genus and family.  The description should be complete for the specimen in hand (certain species have not been fully described yet in this version).  No diagnosis is provided for a genus or a family, something expected in a typical flora, or in a textbook on systematic botany.  This treatment is not intended to be a general plant taxonomy or ecology textbook, and its only real goal is to provide the species descriptions for identification purposes. 

(2) An attempt was made to describe flowers for groups that are often ignored in standard floristic treatments, so that a student of plants can completely understand the flower being examined.  It has not been possible to include all details because fresh materials for certain species were not available ore were inadequate over the duration of the project.  Because this flora is published online, any description can be upgraded if or when better fresh material becomes available  to UCLA researchers.  Hence, this flora will continue to be a work in progress.

(3) New keys were written that avoid hard-to-observe or seasonal features and characteristics, so that the amateur has a reasonable chance at identification.  Professionals tend to use reliable, but often difficult to observe, characteristics, which places a hurdle for the average user.  As much as possible, scientists need to produce floras that eliminate the need for the public to consult with and rely upon herbarium taxonomists.  Not only are taxonomists becoming an endangered species in most academic institutions, but also they cannot on a regular basis be expected to identify plant materials for the general public.  Theoretically, it should be possible to take the identification of even difficult groups out of the hands of specialists and enable field researchers and learned amateurs to make dependable determinations on their own.  To do this, we have attempted to reduce professional, i.e., technical, jargon as much as possible without being incorrect, and in some cases we perhaps erred on not being technical enough to satisfy experts.

(4) Descriptions in this flora were done to be as complete as possible for the populations found in range, excluding internal and anatomical features.  The goal was to provide a description so detailed that there will be no doubt by the observer as to the correct identify of a particular plant.  In most local and regional floras, descriptions have been abbreviated, sometimes extensively so, to save space on the printed page, but that can lead to uncertainty in determinations, even by professional botanists.  Flora of North America has the goal to provide complete descriptions, but treatments of many families have still not been published.  In nearly all cases, the descriptions published here are more detailed than those found elsewhere in the literature, including Flora of North America, which means that an observer will not have to go to another source for missing information.  One disadvantage is that descriptions for our flora do not include the variability found outside the range, hence each may not be entirely encompassing worldwide.  Amazingly, many species described here have never had a thorough description, so that our description will serve that purpose.  The presented descriptions also correct observations on characteristics that are altered by drying, such as sizes, shapes, texture, and color.

(5) We have attempted to avoid citation of literature on the plants described.  References can be found in other treatments, beginning of course with Baldwin et al. (2012) and the on-going Flora of North America.  Our local flora therefore is not meant to be a substitute for the larger works, but mostly a way for amateurs to avoid these as much as possible to save time and limit frustration in dealing with the technical literature.  In our defense, descriptions of plants have traditionally borrowed from earlier descriptions often without having to acknowledge the source and also not citing which material was examined for the description, except, of course, in well-documented monographic treatments, which this is not.

Several popular books on local plants have been available to nonprofessionals to aid in identification and interpretation of vascular plants.  Beginning in the mid-1980s, nonbotanists have had available several useful publications, including Wildflowers of the Santa Monica Mountains (McAuley, 1985), Flowering Plants, the Santa Monica Mountains, Coastal & Chaparral of Southern California (Dale, 1986), and Hiking in Wildwood Regional Park:  Natural History, Folklore, and Trail Guide (Maxwell, 2000).  In addition, there were other pamphlets having checklists of several areas within the range (Muns 1983, 1988a, 1988b).  With the advent of the internet, many online resources have become available for any user, including databases with plant localities, published descriptions of plant species, and now a nearly unlimited source of colored images.  The most useful online resources are those produced by Tony Valois in association with SMMNRA, including the iPhone app “SMM WildFlowers.”  Our description of each plant has been linked to the color images on this particular website and app, so that anyone can consult the description while in the field using a hand-held device without have to carry the heavy two volumes.  By reading through a description, with plant in hand along a hiking trail, the user should be able to determine whether the plant in question fits within the description parameters, and, if the description is reliable, there should be no discrepancies between the observed features and the description.


Descriptions have been drafted to be in parallel as much as we could achieve, with the caveat that even a project spanning nine years of descriptions was not adequate time for two persons to describe so many taxa from living material and complete all the desired and desirable editing.  With such ready access to the internet, all future effective changes will be provided online, and this two-volume set will become the last printed revision.  In fact, likely all floristic treatments have to become electronic, for local to worldwide treatment, and books on the subject will become relicts.

A glossary is provided just before the keys in volume one to explain the technical terms used in the descriptions.  If we have used a more technical term for a particular description, that term will be explained with the term, e.g., pustulate or tuberculate.  In general we have attempted to use descriptors, not used in the glossary, that amateurs should recognize from ordinary life, such as heart-shaped rather than cordate or obcordate, trowel-shaped rather than trullate, top-shaped rather than turbinate, or kidney-shaped rather than reniform.

We have attempted to use several terms consistently for the convenience of the user, which may be objectionable to professional biologists.  For example, regarding leaflike structures within an inflorescence (two or more flowers on a common stalk), we have used the term bractlet as a structure that subtends a pedicel or sessile flower, whereas a bract is any leaflike structure below that point, such as subtending a branch or along the peduncle, and a bracteole is above that point, such as at the end of a pedicel.  The palea of a grass or a sunflower are considered therefore bractlets, whereas the glumes and lemmas of a grass or involucral structures of a sunflower are considered bracts.  This avoids confusion, but of course our convention may be viewed as a setback by researchers who demonstrated that what sometimes  appears to be a bractlet is actually a bract resulting from evolutionary reduction, which we certainly acknowledge.  Related to this, we have mostly tried to treat an inflorescence in a broader sense, as a reproductive unit that begins with turning on a regulatory gene, so that each node above that event bears a flower.  A spike or a raceme of the mustard family (Brassicaceae) is uniformly recognized, but in the evening primrose family (Onagraceae) we describe a leafy spike or raceme whereas others would treat onagrads as having solitary, axillary flowers of cauline leaves.  We have adopted the philosophy therefore that above basal leaves, certain plants are essentially an inflorescence, e.g., in Geraniaceae and Caryophyllaceae.  By and large, most floras have done a poor job of describing inflorescence structure, and consequently the terminology is difficult to standardize.

In this revision scientific names used are, as much as possible, consistent with The Jepson Manual.  Most exceptions were where we disagreed with the statewide treatment regarding varieties or subspecies, because in range the distinctions or similarities could not be defended, and further research is needed to understand the technical distinctions.  On the one hand, collections from a given locality in one year have been determined as one form and in another year a different form, e.g., Arctostaphylos glandulosa and Cercocarpus betuloides.  In other cases, we have recognized species as being distinct, e.g., Thalictrum polycarpum, Astragalus antiselli, and Phoradendron villosum, and that authors missed significant differences that deserve recognition.  Closer attention needs to be given either to variation or discrepancies.  We also try to indicate a variety or subspecies name for our populations, if none is currently accepted.

Because The Naturalist’s Flora was not constrained by governing boards, funding agencies, reviewers and editors, or absolute adherence to either tradition or convention, decisions about scientific names and classification were made, we believed, solely on merit.  For classification, we ascribed to the concept that a taxon must be monophyletic, as determined by cladistics, and that the scientific name is from that a by-product.  As such, we recognized certain distinct genera, e.g., Sairocarpus and Neogaerrhinum (from Antirrhinum), but not others, e.g., California (in Erodium) or Stebbinsoseris and Uropappus (in Microseris).  We included several species that are not included in The Jepson Manual, e.g., Tillandsia usneoides and Pistia stratiodes.  We had no issues with recognizing legal generic and families names, even if they confuse amateurs, but erred to be consistent with cladistic and monophyletic principles, and rejected those we judged not to be worthy.  We rejected as polyphyletic certain commonly used names for interspecific hybrids (in Equisetum and Opuntia).  In the case of lacepods, we recognized Thysanocarpus conchuliferus, a listed species considered endemic to Santa Cruz Island to be the same as populations in SMM, and doubted the validity of the listed Cercocarpus betuloides var. blanchiae of Santa Catalina Island being in range.  But by and large the names used in this review follow very closely Baldwin (2012), and were made in respectful consultation with The Jepson Manual project.

Revision of the local flora was begun in March, 2001, when a survey by Prigge was launched on the vascular plants correctly vouchered from range.  Beginning in 2003, there has been an attempt to locate or “rediscover” any species reported from range, so that it could be described from living, local materials, as well as verified as still occurring locally.  The rediscovery process, and to obtain fresh materials of each taxon at all phases of its life cycle, was an arduous one assisted by a number of field workers, but especially SMMNRA Tarja Sagar and Tony Valois and environmental consultants Carl Wishner and Dan Cooper deserve special recognition, and without whom this project would not have been successful.  Except for vouchers of discoveries and representation from SH, no major effort was made to collect plants within the range, because of time conflicts with describing the plants, which itself was a fulltime job over nine years.  Physical sightings accounted for observations on plant sizes and flowering dates that are not always reliably obtained from herbarium materials.  Thus, we record all known flowers, regardless of abundance and year, rather than peak flowering time, but one can assume that the peak flowering in most circumstances will be within the middle fifty percent.

Flowering period

Records from herbarium vouchers were combined with personal field observations by the authors and other skilled observers to provide the known flowering period of each taxon within the range.  Mid-April to mid-May are peak flowering weeks for the entire local flora, i.e., when approximately three-quarters of the species may be observed somewhere in range with open flowers.  For more than two-thirds of these species, the peak flowering month also occurs during springtime.  Fewer species produce flowers during summer months, but numerous species have peak flowering during drought of summer or early fall.  The lowest level of flowering, as judged by number of taxa and magnitude, occurs from late October through early December.  For November, when broad patches of vegetation often exhibit no flowers at all, there exist flowering records for SMM/SH of about 150 taxa, most of which are holdovers from fall-flowering episodes, and others can be expected with future botanizing during November.  [[(Parentheses are used in instances where flowering for a given month is extremely rare.)]]

Relatively few species can be found flowering during every week somewhere in range, and even the most successful weedy species, such as Ricinus communis, Helianthus annuus, and Taraxacum officinale, which can flower anytime when soil remains moist, by and large are seasonal.  Malacothamnus fasciculatus, Malacothrix saxatilis, and Calystegia macrostegia are unusual natives because they may facultatively form new shoots with flowers during any month following drenching rains, but they can also lack flowers for many months at dry locations.  The threatened Deinandra minthornii, which only grows around sandstone rock outcrops, can have winter and summer flowering seasons (2003) and, hence, may be expected to flower at a site during any wet season that initiates a new flush of growth.

Year-to-year variations for first-observed anthesis, flower abundance, and duration of the flowering period are very striking.  Fortunately, all extremes were recently experienced:  2002 and 2007 were so dry that the spring flora was very depauperate and flowering effort was weak; very early flowering for many species followed heavy October and record-setting December rains in 2004; a long-protracted rainy season in 2003 permitted spring-flowering species to produce some blossoms as late as mid-summer, and for certain species of Ceanothus to have a second, summer flowering event; prolonged cold temperatures during November and December 2003 postponed the onset of flowering by nearly a month; and a very warm but dry fall in 2007 stimulated flowering of certain chaparral shrubs in early November.  On 12 January 2007, approximately five centimeters of snow accumulated in chaparral above Malibu along Malibu Canyon Road; strange as it may seem, in that same part of the SMM pockets of cold air during winter can be enough to freeze native shrubs, especially Malosma laurina (Davis 2007).

Between-year differences for first anthesis of woody and herbaceous perennials can be up to six weeks apart, e.g., Arctostaphylos glauca  (15 November 2004 vs. 27 December 2003).  Open flowers on A. glauca, Ceanothus megacarpus, Ribes malvaceum var. viridifolium, and in particular R. indecorum are indicators that the 10-month parade of flowering has begun for undisturbed chaparral.  The flowering season can be truncated during very dry years and at extremely dry sites, and greater than half of the herbaceous species may never appear and flower during a drought year, such as 2002 and 2007 (< 7 cm total rainfall during the growing season).

Flowering for a particular species or a vegetation type is never uniform throughout the range.  For SMM/SH, no study has quantified how differences in local air temperature and humidity, soil temperature and moisture, or light intensity affect the start and end of flowering.  Nonetheless, naturalists commonly observe that the warmest microhabitats, such as sandy coastal bluffs, sunny south-facing slopes, and roadsides and disturbed lots, are places where early flowering for species is often seen, whereas cool and shady microhabitats are where one expects to find late-flowering individuals.  For example, the population of Croton californicus may be found in full flower during early November on coastal bluffs at Point Dume (SMM), but an interior population in coastal sage scrub on the Chatsworth Reservoir (SH) only begins flowering in April.  Across the range, individuals of amentiferous trees, such as oaks (Quercus), California black walnut (Juglans californica), and white alder (Alnus rhombifolia), vary greatly in date of first release of pollen.  During December or even November, when soil is cold, the trailing, climbing shoots of man-root (Marah macrocarpa) begin to emerge from massive storage roots and soon form male flowers, whereas the other geophytic cucurbit vine Cucurbita foetidissima requires warmer soil in mid-spring for shoot production and flowers in late spring and especially during summer.  In general, growth and flowering of geophytic species are greatly reduced or stopped during very dry years or at very dry sites, but with diligent searching flowers can usually be observed at a microhabitat somewhere within the range.  An exception is Muilla maritima, known from one general location in the SH, where from 2001-2007 it only emerged in spring of 2001 and 2005; this geophyte seems to require a specific regime of rainfall and temperature to grow in a particular spring.

The text of the above Introduction used with permission from

A Naturalist's Flora of the Santa Monica Mountains and Simi Hills, California

Barry A. Prigge and Arthur C. Gibson

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