Plant Species of the Borrego Desert: The Nifty Fifty: The 51 Most Common Species

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Table of Contents

Introduction
Analysis of the List
The Checklist
     Sort by Abundance
     Sort by Family

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Introduction

The page gives the most common 51 species of the Borrego Desert. Those top 51 species are defined as those occurring in nine or more of the 24 individual surveys I've done as of 29 December 2008. (OK, one more than 50, but Nifty Fifty sounds better than Nifty Fifty-one, and matches the name of the popular common stocks of the 1960s and 1970s. Artistic license, you know.)

Caution: this list is preliminary, and should not be used for scientific purposes until I've finished my flora of the Borrego Desert. In particular, the results may change in the future as more fieldwork is done and more of my previous fieldwork is digitized, especially as more survey locations are added and more fieldwork is done when annuals are present.

To help understand what this list represents, it may help to understand examples of what this list does not represent:

• This is not a list of the most common plants in any one specific area or habitat. For that purpose, consult the Floras and Plant Trail Guides for specific areas.

• This is not a list of the most common plants seen in the peak flowering season, or at any other particular time of year.

• This is not a list of the most abundant plants throughout the entire surveyed area.

• This is not a list of my personal favorite species.

For example, this list does not contain many of the common species found in the sandy habitat along Henderson Canyon and Di Giorgio Roads such as hairy sand verbena, Abronia villosa var. villosa; desert dicoria, Dicoria canescens; and hairy desert-sunflower, Geraea canescens. Those species have been found, respectively, in only 2, 5, and 2 of my 24 surveyed areas so far. Although those species are both common and widespread because their habitat is common and widespread along the desert floor, their habitat is not found in most of my surveyed areas, and thus these species don't make the list here.

This example of plants confined to a specific habitat gives insight into what the list presented here actually represents. Most species are like the three species mentioned above, confined to a single habitat. Examples of habitats and species confined to that habitat, along with the number of survey areas in which each named species was found, are given in the following table:

Habitat	Species confined to that Habitat		# Survey Areas
	Common Name	Scientific Name
Gravelly washes subject to flooding that scarifies seeds	smoke tree	Psorothamnus spinosus	13
Moderately saline areas	four-wing saltbush	Atriplex canescens	8
Steep canyon walls of solid rock	arrow-leaf	Pleurocoronis pluriseta	6
Seeps, springs, streamsides	California fan palm	Washingtonia filifera	3
Rocky slopes among boulders	pygmy-cedar	Peucephyllum schottii	3
Sandy places	hairy sand verbena	Abronia villosa var. villosa	2
Extremely saline areas	iodine-bush	Allenrolfea occidentalis	2
Permanent streams	Fremont cottonwood	Populus fremontii	2

Of the species in the above table, only smoke tree, Psorothamnus spinosus, exceeds the cutoff of 9 or more survey areas and is present in the top 51 list here. Even though it is confined to a very specific habitat, that habitat is widespread through my surveyed areas. Four-wing saltbush, Atriplex canescens, just misses the cut-off. Its habitat of moderately saline areas is fairly widespread, but not quite enough to make the cutoff here.

In addition, many species are confined to geographic habitats with specific sets of conditions. Some of these habitats can be easily understood by mere mortals, such as the species that are confined to the Desert Transition Zone near the east base of the Peninsular Range where they find the only combination of heat, rainfall and cold that they can thrive in. Examples are desert apricot, Prunus fremontii; and lotebush, Ziziphus parryi, each found in two surveyed areas. Other species seem to be confined to specific habitats that are hard for humans to comprehend.

To see what the list does represent, here are the habitats of the two species found in all 24 surveyed areas. Burroweed, Ambrosia dumosa, is said to grow in Creosote Bush Scrub, meaning it grows essentially everywhere that the other top species, creosote, Larrea tridentata, grows. Creosote gives its name to its plant community, since it grows almost everywhere in the Sonoran desert, thriving in or at least tolerating a large number of habitats, under many different geographic conditions.

Those two species are not picky about where they grow, and are among the small number of species that successfully grow in many different conditions. In fact, Forrest Shreve, in Vegetation and Flora of the Sonoran Desert, says that these two species vastly outnumber all others in the Lower Colorado Valley subdivision, which includes the Borrego Desert (p. 49). The primary reason for this dominance is that these are the last two shrub species to drop out as the rainfall diminishes.

Note that such widespread common species are rare; see the histogram below that demonstrates the well-known biological law that common species are few in number; rare species are common in number.

Many of the other species on the list are similar non-picky species, but many others occur in specific habitats that are found in nearly every surveyed area, such as smoke tree. Other examples are cheesebush, Ambrosia salsola var. salsola; and desert-lavender, Condea emoryi, which grow in any wash that has enough seasonal moisture for them.

Important Caveats:

• Annuals and perennials are often wildly underestimated in many of these surveys, since about half of the surveys were done outside the narrow window in which many such species can be found and confidently identified. Thus the survey can be considered complete only for shrubs, cacti, trees, and those annuals or perennials that can be confidently identified from dead plant remnants.

  Cryptantha species may suffer most from underestimation since one needs live plants with mature fruit to confidently identify them. Probably due to the short window for confident identification, no Cryptantha species made the list. The most abundant species, C. barbigera, just missed the cutoff, being seen so far in 8 of these surveys. It is highly likely that C. barbigera and C. angustifolia will be present on the list after all 24 surveys have been surveyed in prime time.

  However, since about ten of the surveys were done in prime time, very widespread annuals and perennials had at least some chance to make this list. In fact, half the list consists of annuals and perennials.

• Note that my definition of the Borrego Desert above is the portion in the 24 individual surveys carried out so far. This is a pretty restrictive definition; see the map below showing the surveyed areas. There are large areas of the Borrego Desert not yet surveyed, and the current list given here may change as more areas are sampled.

• Note that the definition of Common used above means that these species are simply widespread among my survey locations, and not necessarily abundant. It only takes a single individual to be counted in a survey, so rare but widespread species will appear in this list alongside very abundant and widespread species.

  However, in fact, nearly all of these species are also quite abundant. A future version of this list will include the abundances from each survey.

The following map of the Borrego Desert shows where the surveys have been conducted so far:

Each dot roughly corresponds to the midpoint of each survey. Most of these surveys are detailed in preliminary Floras and Plant Trail Guides.

Each survey typically covered a linear distance of four miles or so, sometimes along a single trail and sometimes along a loop. The elevations surveyed ranged from 200 feet in the extreme northeast corner of the county, to 2600 feet in Hellhole Canyon. The mean elevation of the surveys was 1000 feet, with most of the area surveyed between 500 and 1500 feet. Note that the map above shows the 1000 foot and 3000 foot elevation contours.

This page can be used by beginning students of the Borrego Desert flora as a list of species to learn first, as well as by photographers trying to learn the species name for a common flower they photographed without having to wade through the 373 species I've observed so far, or the 641 species including records from others from this entire area. People familiar with the Borrego Desert can check to see if they know all of the top 51 species.

For those itching to know the next most common species, see The 172 Most Common Species, which includes the top 51 species.

Analysis of the List

The following histogram gives the number of surveys in which each taxon was found:

This histogram follows the usual shape, in which only a very few species are ubiquitous, with most species being found in only one or two surveys. Hence the statement above that common species are few in number; rare species are common in number. For more information on how this histogram was derived, and why this is the usual shape, see How Common Are The Plants Of Southern California? and Plants of Southern California: Introduction and Explanation of Trail Guides. The plotted curve through the data points is a fairly good fit, indicating that survey incompleteness is not a significant factor overall.

The following histogram gives the number of species in this list by plant habit, sorted first alphabetically by habit and then sorted by abundance:

Sort Alphabetically By Habit						Sort Numerically By Abundance
Habit	H	#	%			Habit	H	#	%
Annual	A	18	35%			Annual	A	18	35%
Cactus	C	6	12%			Shrub / Subshrub	S	17	33%
Fern	F	1	2%			Perennial	P	8	16%
Perennial	P	8	16%			Cactus	C	6	12%
Shrub / Subshrub	S	17	33%			Fern	F	1	2%
Tree	T	1	2%			Tree	T	1	2%

The column H gives the abbreviation used for the plant habit in the checklists below.

The Checklist

The Nifty Fifty are presented in two ways below. In both versions, the Family and Scientific Name are from the Jepson eflora as of 10 January, 2023. An asterisk before the Common Name indicates a non-native taxon. #S is the number of surveys in which each taxon was found. H is the abbreviation used for the plant habit, given in the table above.

First, the checklist is presented in descending order of abundance, sorted by the number of surveys in which each taxon was found. Second, it is presented in traditional family order: sorted first by category - ferns, eudicots, and monocots - and then by family and scientific name.

The checklist contains Krameria grayi, but not its sister species of Krameria erecta. These two species are very difficult to tell apart without fruit, which is not always present, and thus readers may wonder how common K. erecta is. K. erecta appears in 8 lists, and thus just missed the cutoff of 9, compared to the 18 lists that contained K. grayi.

In the following two checklists, the Scientific Names have been updated by Don Rideout from the 1993 Jepson Manual system to the names used the Jepson eflora as of 10 January 2023.

The Checklist Sorted by Abundance

#	#S	H	JM Family	Scientific Name	(*)Common Name
1	24	S	Asteraceae	Ambrosia dumosa	burroweed
2	24	S	Zygophyllaceae	Larrea tridentata	creosote bush
3	23	S	Fabaceae	Psorothamnus schottii	indigo bush
4	22	S	Asteraceae	Encelia farinosa	brittlebush
5	22	P	Euphorbiaceae	Euphorbia polycarpa	small-seeded spurge
6	22	S	Fouquieriaceae	Fouquieria splendens ssp. splendens	ocotillo
7	21	S	Asteraceae	Ambrosia salsola var. salsola	cheesebush
8	21	A	Brassicaceae	Brassica tournefortii	*Asian mustard
9	21	A	Onagraceae	Eulobus californicus	California suncup
10	21	P	Poaceae	Hilaria rigida	big galleta
11	19	S	Asteraceae	Bebbia juncea var. aspera	sweetbush
12	19	P	Asteraceae	Stephanomeria pauciflora var. pauciflora	wire-lettuce
13	19	S	Fabaceae	Senegalia greggii	catclaw
14	19	S	Lamiaceae	Condea emoryi	desert-lavender
15	18	S	Krameriaceae	Krameria bicolor	white rhatany
16	17	C	Cactaceae	Cylindropuntia ganderi	Gander's cholla
17	17	C	Cactaceae	Opuntia basilaris var. basilaris	beavertail cactus
18	17	A	Plantaginaceae	Plantago ovata	desert plantain
19	17	P	Polygonaceae	Eriogonum inflatum	desert trumpet
20	16	C	Cactaceae	Ferocactus cylindraceus	California barrel cactus
21	15	A	Asteraceae	Perityle emoryi	Emory's rock-daisy
22	14	A	Onagraceae	Eremothera boothii ssp. condensata	Booth's evening primrose
23	14	A	Polygonaceae	Chorizanthe brevicornu var. brevicornu	brittle spineflower
24	14	P	Viscaceae	Phoradendron californicum	desert mistletoe
25	13	T	Fabaceae	Psorothamnus spinosus	smoke tree
26	13	A	Onagraceae	Chylismia claviformis ssp. peirsonii	brown-eyed primrose
27	13	A	Poaceae	Schismus barbatus	*Mediterranean schismus
28	12	A	Brassicaceae	Lepidium lasiocarpum var. lasiocarpum	hairy-podded pepper-grass
29	12	C	Cactaceae	Cylindropuntia echinocarpa	silver cholla
30	12	A	Hydrophyllaceae	Phacelia distans	common phacelia
31	12	S	Zygophyllaceae	Fagonia laevis	California fagonia
32	11	A	Asteraceae	Rafinesquia neomexicana	desert chicory
33	11	C	Cactaceae	Cylindropuntia bigelovii	teddy-bear cholla
34	11	P	Euphorbiaceae	Ditaxis lanceolata	narrowleaf ditaxis
35	11	A	Fabaceae	Lupinus arizonicus	Arizona lupine
36	11	A	Hydrophyllaceae	Phacelia crenulata var. ambigua	heliotrope phacelia
37	11	A	Loasaceae	Mentzelia involucrata	bracted blazing star
38	11	S	Loasaceae	Petalonyx thurberi ssp. thurberi	Thurber's sandpaper-plant
39	11	P	Malvaceae	Hibiscus denudatus	rock hibiscus
40	11	P	Nyctaginaceae	Mirabilis laevis var. retrorsa	wishbone plant
41	10	C	Cactaceae	Cylindropuntia ramosissima	pencil cholla
42	10	A	Fabaceae	Lupinus concinnus	bajada lupine
43	10	S	Fabaceae	Psorothamnus emoryi	Emory's indigo-bush
44	10	A	Geraniaceae	Erodium cicutarium	*redstem filaree
45	10	A	Lamiaceae	Salvia columbariae	chia
46	9	A	Asteraceae	Senecio mohavensis	Mojave ragwort
47	9	S	Asteraceae	Trixis californica var. californica	California trixis
48	9	S	Boraginaceae	Tiquilia palmeri	Palmer's coldenia
49	9	S	Chenopodiaceae	Atriplex hymenelytra	desert holly
50	9	S	Chenopodiaceae	Atriplex polycarpa	cattle saltbush
51	9	F	Pteridaceae	Myriopteris parryi	woolly lipfern

The Checklist Sorted by Family

#	#S	H	JM Family	Updated Scientific Name	(*)Common Name
1	9	F	Pteridaceae	Myriopteris parryi	woolly lipfern
2	24	S	Asteraceae	Ambrosia dumosa	burroweed
3	21	S	Asteraceae	Ambrosia salsola var. salsola	cheesebush
4	19	S	Asteraceae	Bebbia juncea var. aspera	sweetbush
5	22	S	Asteraceae	Encelia farinosa	brittlebush
6	15	A	Asteraceae	Perityle emoryi	Emory's rock-daisy
7	11	A	Asteraceae	Rafinesquia neomexicana	desert chicory
8	9	A	Asteraceae	Senecio mohavensis	Mojave ragwort
9	19	P	Asteraceae	Stephanomeria pauciflora var. pauciflora	wire-lettuce
10	9	S	Asteraceae	Trixis californica var. californica	California trixis
11	9	S	Boraginaceae	Tiquilia palmeri	Palmer's coldenia
12	21	A	Brassicaceae	Brassica tournefortii	*Asian mustard
13	12	A	Brassicaceae	Lepidium lasiocarpum var. lasiocarpum	hairy-podded pepper-grass
14	11	C	Cactaceae	Cylindropuntia bigelovii	teddy-bear cholla
15	12	C	Cactaceae	Cylindropuntia echinocarpa	silver cholla
16	17	C	Cactaceae	Cylindropuntia ganderi	Gander's cholla
17	10	C	Cactaceae	Cylindropuntia ramosissima	pencil cholla
18	16	C	Cactaceae	Ferocactus cylindraceus	California barrel cactus
19	17	C	Cactaceae	Opuntia basilaris var. basilaris	beavertail cactus
20	9	S	Chenopodiaceae	Atriplex hymenelytra	desert holly
21	9	S	Chenopodiaceae	Atriplex polycarpa	cattle saltbush
22	11	P	Euphorbiaceae	Ditaxis lanceolata	narrowleaf ditaxis
23	22	P	Euphorbiaceae	Euphorbia polycarpa	small-seeded spurge
24	11	A	Fabaceae	Lupinus arizonicus	Arizona lupine
25	10	A	Fabaceae	Lupinus concinnus	bajada lupine
26	10	S	Fabaceae	Psorothamnus emoryi	Emory's indigo-bush
27	23	S	Fabaceae	Psorothamnus schottii	indigo bush
28	13	T	Fabaceae	Psorothamnus spinosus	smoke tree
29	19	S	Fabaceae	Senegalia greggii	catclaw
30	22	S	Fouquieriaceae	Fouquieria splendens ssp. splendens	ocotillo
31	10	A	Geraniaceae	Erodium cicutarium	*redstem filaree
32	11	A	Hydrophyllaceae	Phacelia crenulata var. ambigua	heliotrope phacelia
33	12	A	Hydrophyllaceae	Phacelia distans	common phacelia
34	18	S	Krameriaceae	Krameria bicolor	white rhatany
35	19	S	Lamiaceae	Condea emoryi	desert-lavender
36	10	A	Lamiaceae	Salvia columbariae	chia
37	11	A	Loasaceae	Mentzelia involucrata	bracted blazing star
38	11	S	Loasaceae	Petalonyx thurberi ssp. thurberi	Thurber's sandpaper-plant
39	11	P	Malvaceae	Hibiscus denudatus	rock hibiscus
40	11	P	Nyctaginaceae	Mirabilis laevis var. retrorsa	wishbone plant
41	13	A	Onagraceae	Chylismia claviformis ssp. peirsonii	brown-eyed primrose
42	14	A	Onagraceae	Eremothera boothii ssp. condensata	Booth's evening primrose
43	21	A	Onagraceae	Eulobus californicus	California suncup
44	17	A	Plantaginaceae	Plantago ovata	desert plantain
45	14	A	Polygonaceae	Chorizanthe brevicornu var. brevicornu	brittle spineflower
46	17	P	Polygonaceae	Eriogonum inflatum	desert trumpet
47	14	P	Viscaceae	Phoradendron californicum	desert mistletoe
48	12	S	Zygophyllaceae	Fagonia laevis	California fagonia
49	24	S	Zygophyllaceae	Larrea tridentata	creosote bush
50	21	P	Poaceae	Hilaria rigida	big galleta
51	13	A	Poaceae	Schismus barbatus	*Mediterranean schismus

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I thank Bill Sullivan for discussions which stimulated the extensive discussion in the Introduction about what this list does and does not represent. I thank Don Rideout for updating the scientific names in the two checklists.

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