Anza-Borrego: Plant Guide To Visitor Center Plantings

This is a working list, about which we make no guarantees at all until we officially release it. Use at your own risk!

Introduction and Explanation of Plant Trail Guides
Introduction
Highlights of This Trail
Fieldwork Dates and Summary of List Changes With Time
The Plant Guide
Comments On Specific Species
Introduction

This plant trail guide is to the plantings immediately adjacent to the Visitor Center. The 0.15 mile route is all on paved sidewalk, beginning at the parking lot and looping around the Visitor Center. (The sidewalk actually goes on top of the Visitor Center, which is built into a hill, so it technically only loops around the front of the Visitor Center.)
The garden has beautiful plantings, and best of all, nearly all of the species are labeled. On the route described here, 21 of the 26 taxa are labeled with both the common and Latin names.
Four of the other five taxa were easily identified using the wonderful book Cacti, Shrubs and Trees of Anza-Borrego: An Amateur's Key to Identifying Desert Plants when they are without flowers, by Paul R. Johnson. The fifth taxon was a grass, easily identified from a plant list compiled by Michael Simpson.
This is the best place to begin learning the plants of Anza-Borrego, which Tom knows from experience. When Tom first did this trail, having never botanized the desert before, he was only familiar with four of the 26 taxa. With Paul's Key in hand, two hours spent with these plants gave Tom enough confidence in recognizing and keying out these plants to begin plant guides for Anza-Borrego trails.
Highlights of This Trail

The taxa found on this Sonoran Desert Trail are almost completely different from the taxa found in our other plant guides to date, which have been in the mountains (the San Gabriels, San Bernardinos, San Jacintos, Palomar and the Cuyamacas); in the coastal regions (Crystal Cove and Torrey Pine Beach areas); and in low inland coastal areas (Fallbrook; Santa Margarita Ecological Reserve; Santa Rosa Plateau Ecological Reserve, and Blue Sky Ecological Reserve). Only four of the 26 taxa were recorded on any of the previous 37 trails in our database. Even those four are mostly due to desert species which have extended their range from the Baja California deserts into San Diego County coastal regions, which receive the lowest rainfall of all of our other plant guide trails.
Most interesting is that many of these taxa are "single children", in that they are the only species, or one of the few species, in their genus and sometimes even the only genus in their family. Others are the only representatives of their genus in California or even the United States. The following table gives some examples:

Common Name Latin Name Distribution
ironwood Olneya tesota only sp in genus
blue palo verde Cercidium floridum ssp. floridum only 4 spp in genus; only 2 here
ocotillo Fouquieria splendens ssp. splendens the only genus in family; only 11 spp.
creosote bush Larrea tridentata only 5 spp in genus; only one here
jojoba Simmondsia chinensis only genus in family; only sp in genus
elephant tree Bursera microphylla only sp here of 60 spp in genus; 17 genera in family
catclaw Acacia greggii only native sp in genus
desert lavender Hyptis emoryi only sp here
California trixis Trixis californica var. californica only sp here
chuparosa Justicia californica only one here out of 300 spp in tropics and subtropics

Clearly, this is telling us something important about the cactus, shrubs and trees (CST below) of this lower desert flora. We don't know for sure what this means, and the Jepson Desert Manual, oddly, does not even give any mention of this "single children" aspect of the flora. Possible reasons are:

The CST desert flora is young, and hasn't been around long enough to develop more species; and/or
The CST desert flora is derived from species that are at the extreme limits of their range, so that only a few species in some families are able to survive here; and/or
The desert environment is so harsh that only a few CST species in some families are able to survive here; and/or
The CST desert flora went through a recent evolutionary bottleneck, or "crunch", in which the number of species was severely restricted.
It seems probable that the CST flora did experience such a recent bottleneck. The Jepson Desert Manual mentions that the present flora of the Sonoran Desert has only arrived there in the last 10,000 years, after the last glacial period. Prior to 10,000 years ago, the flora was one of pinyons, junipers, and other species typical now of desert uplands. At that time, the present flora was restricted to a much smaller area around the lower Colorado River and south in Mexico.
As the Sonoran desert grew in the last 10,000 years, the species simply expanded their range. Since 10,000 years is less than 1% of the typical speciation timescale of ~1 million years, there has been no time for evolution to produce new species. Hence the number of species in the CST desert flora has remained that corresponding to the much smaller area it was restricted to 10,000 years ago. (See Introduction and Explanation of Trail Guides, as well as some of the analysis pages on this site, for more information about the species - area relationship.)

Of course, it is possible that many or all of the above factors operate simultaneously to account for the "single children" effect.
The other noticeable feature of the flora on this trail is the dominance by the Fabaceae family. There are six taxa from that family, 23% of the 26 total taxa, equaling the six taxa from the Cactaceae family, and only four taxa by the usual ubiquitous Asteraceae family. When one thinks of the desert, one usually thinks of cactus. But if this planted area is any guide, one should equally well think of the pea family!
Finally, an amusing sidenote: the families represented here include the first (Acanthaceae) and last (Zygophyllaceae) dicot families in alphabetical order.
Number of Unique Taxa On This Trail

The following histogram gives the number of trails in our database that contain each taxon on this trail. We had 38 trails in our database when this histogram was made. A number of "1" means the taxon has only been found only on this list, among all the trails in our database.

Number of Trails
Containing A Taxon Number Of Taxa
On This Trail % of Taxa
On This Trail
1 22 85%
2 1 4%
3 2 8%
4 1 4%
Total Taxa 26 100%

Fieldwork Dates and Summary of List Changes With Time

The following table gives the dates the trail was walked and taxa recorded. After each visit, the tables gives the total number of taxa on the list and the breakdown of the taxa without positive identification. See Explanation of Plant Trail Guides to understand the symbols below.

Visit Date Visit # # taxa # "?" # "sp" # "~" # "ssp"
12/31/2002 1 26 0 0 0 2

The Plant Guide

This plant guide is unusual in that a number of species are listed twice. The first occurrence is listed and numbered, as always. In addition, all labeled species are listed as well, each time they occur. These specimens are identified by Lbl in the id column. If the common name or latin name on the label differs from the one we use, the latin name contains a link to comments below giving the differences.
Version for printing, without lines and other text on this page (3 pages)

mile s # id Common Name Latin Name #here #all
0.00 This guide begins at the main pathway to the Visitor Center from the Parking Area. The tall flagpole is of this pathway immediately to the left.
0.00 Sign on left: "Anza-Borrego Desert State Park Visitor Center 100 yards (ahead)"; trashcans on right.
0.00 r 1 ssp California barrel cactus Ferocactus cylindraceus var. lecontei / 1
0.00 l 2 indigo bush Psorothamnus schottii / 1
0.00 b 3 brittlebush Encelia farinosa / 3
0.00 r 4 blue palo verde Cercidium floridum ssp. floridum / 1
0.00 l 5 honey mesquite Prosopis glandulosa var. torreyana / 2
0.00 r 6 chuparosa Justicia californica / 1
0.00 l 7 burroweed Ambrosia dumosa / 1
0.00 l Flagpole.
0.00 r 8 ocotillo Fouquieria splendens ssp. splendens / 1
0.00 r Display Board
0.01 l 9 Lbl ironwood Olneya tesota⁺ / 1
0.01 Jct. alternate sidewalk from parking lot coming in from right. Y-jct ahead - left goes directly to Visitor Center; go right, signed "Bridge Overlook". Plaque on boulder on right: "Newt and Mary Ann Williams Garden".
0.01 r Lbl honey mesquite Prosopis glandulosa var. torreyana⁺ /
0.01 r 10 Lbl Engelmann's hedgehog cactus Echinocereus engelmannii⁺ / 1
0.01 r 11 creosote bush Larrea tridentata / 1
0.01 r 12 prickly pear Opuntia phaeacantha / 1
0.01 l 13 jojoba Simmondsia chinensis / 1
0.01 r 14 Lbl Mohave yucca Yucca schidigera / 3
0.02 l Lbl jojoba Simmondsia chinensis /
0.02 r Lbl prickly pear Opuntia phaeacantha /
0.02 r 15 Lbl pencil cactus Opuntia ramosissima / 1
0.02 l Jct. sidewalk connecting direct Visitor Center path with this path.
0.03 r 16 silver cholla Opuntia echinocarpa / 1
0.04 l 17 ssp cheesebrush Hymenoclea salsola var. salsola / 1
0.04 l 18 big galleta Pleuraphis rigida / 1
0.04 Enter area on top of Visitor Center with benches and labeled skyline maps.
0.04 r 19 desert agave Agave deserti / 1
0.06 Leave area on top via steps down.
0.07 l 20 Lbl beavertail cactus Opuntia basilaris var. basilaris⁺ / 4
0.07 l Lbl Engelmann's hedgehog cactus Echinocereus engelmannii /
0.07 Jct with cross-sidewalk. Sign ahead: "Edith Meyerson Nierenberg Plaza dedicated 1996". Turn left toward Visitor Center.
0.08 r 21 Lbl California trixis Trixis californica var. californica / 1
0.08 r Lbl ironwood Olneya tesota⁺ /
0.09 Bicycle racks on right; bathrooms on left.
0.10 r Lbl silver cholla Opuntia echinocarpa⁺ /
0.10 r Lbl ocotillo Fouquieria splendens ssp. splendens⁺ /
0.10 Visitor Center entrance on left; map of immediate vicinity on right.
0.12 r 22 Lbl elephant tree Bursera microphylla / 1
0.13 r Lbl creosote bush Larrea tridentata /
0.13 r Sign: "Desert pupfish sanctuary" next to shallow pond with pupfish.
0.13 r Lbl indigo bush Psorothamnus schottii /
0.13 r 23 Lbl California fan palm Washingtonia filifera / 1
0.14 r 24 Lbl catclaw Acacia greggii / 1
0.14 r 25 Lbl smoke tree Psorothamnus spinosus / 1
0.15 l Jct. sidewalk connecting to Bridge Overloop sidewalk.
0.15 l Lbl California barrel cactus Ferocactus cylindraceus var. lecontei⁺ /
0.15 r Lbl chuparosa Justicia californica⁺ /
0.15 l 26 Lbl desert lavender Hyptis emoryi / 1
0.15 r Lbl blue palo verde Cercidium floridum ssp. floridum⁺ /
0.15 r Jct. Nature Loop Trail. Sign: "Nature Loop Trail 0.25 mile loop; Campground 0.6 mile".
0.15 End of this guide at the junction with the beginning of the loop at mile 0.01.

Comments On Specific Species

Various species. The variety name is not given on the labels.
Various species. The subspecies name is not given on the labels.
Olneya tesota. This species is called desert ironwood on the label.
Echinocereus engelmannii. The label gives the former ssp name of engelmannii.
Opuntia echinocarpa. The species is called cane cholla on the label, with the former variety name of wolfii.
Ferocactus cylindraceus var. lecontei. The species is called just barrel cactus on the label, with the former latin name of Ferocactus acanthodes.
Justicia californica. The species is labeled with its former latin name of Beloperone californica.

Common Name	Latin Name	Distribution
ironwood	Olneya tesota	only sp in genus
blue palo verde	Cercidium floridum ssp. floridum	only 4 spp in genus; only 2 here
ocotillo	Fouquieria splendens ssp. splendens	the only genus in family; only 11 spp.
creosote bush	Larrea tridentata	only 5 spp in genus; only one here
jojoba	Simmondsia chinensis	only genus in family; only sp in genus
elephant tree	Bursera microphylla	only sp here of 60 spp in genus; 17 genera in family
catclaw	Acacia greggii	only native sp in genus
desert lavender	Hyptis emoryi	only sp here
California trixis	Trixis californica var. californica	only sp here
chuparosa	Justicia californica	only one here out of 300 spp in tropics and subtropics

Number of Trails Containing A Taxon	Number Of Taxa On This Trail	% of Taxa On This Trail
1	22	85%
2	1	4%
3	2	8%
4	1	4%
Total Taxa	26	100%

Visit Date	Visit #	# taxa	# "?"	# "sp"	# "~"	# "ssp"
12/31/2002	1	26	0	0	0	2

mile	s	#	id	Common Name	Latin Name	#here	#all
0.00				This guide begins at the main pathway to the Visitor Center from the Parking Area. The tall flagpole is of this pathway immediately to the left.
0.00				Sign on left: "Anza-Borrego Desert State Park Visitor Center 100 yards (ahead)"; trashcans on right.
0.00	r	1	ssp	California barrel cactus	Ferocactus cylindraceus var. lecontei	/	1
0.00	l	2		indigo bush	Psorothamnus schottii	/	1
0.00	b	3		brittlebush	Encelia farinosa	/	3
0.00	r	4		blue palo verde	Cercidium floridum ssp. floridum	/	1
0.00	l	5		honey mesquite	Prosopis glandulosa var. torreyana	/	2
0.00	r	6		chuparosa	Justicia californica	/	1
0.00	l	7		burroweed	Ambrosia dumosa	/	1
0.00	l			Flagpole.
0.00	r	8		ocotillo	Fouquieria splendens ssp. splendens	/	1
0.00	r			Display Board
0.01	l	9	Lbl	ironwood	Olneya tesota⁺	/	1
0.01				Jct. alternate sidewalk from parking lot coming in from right. Y-jct ahead - left goes directly to Visitor Center; go right, signed "Bridge Overlook". Plaque on boulder on right: "Newt and Mary Ann Williams Garden".
0.01	r		Lbl	honey mesquite	Prosopis glandulosa var. torreyana⁺	/
0.01	r	10	Lbl	Engelmann's hedgehog cactus	Echinocereus engelmannii⁺	/	1
0.01	r	11		creosote bush	Larrea tridentata	/	1
0.01	r	12		prickly pear	Opuntia phaeacantha	/	1
0.01	l	13		jojoba	Simmondsia chinensis	/	1
0.01	r	14	Lbl	Mohave yucca	Yucca schidigera	/	3
0.02	l		Lbl	jojoba	Simmondsia chinensis	/
0.02	r		Lbl	prickly pear	Opuntia phaeacantha	/
0.02	r	15	Lbl	pencil cactus	Opuntia ramosissima	/	1
0.02	l			Jct. sidewalk connecting direct Visitor Center path with this path.
0.03	r	16		silver cholla	Opuntia echinocarpa	/	1
0.04	l	17	ssp	cheesebrush	Hymenoclea salsola var. salsola	/	1
0.04	l	18		big galleta	Pleuraphis rigida	/	1
0.04				Enter area on top of Visitor Center with benches and labeled skyline maps.
0.04	r	19		desert agave	Agave deserti	/	1
0.06				Leave area on top via steps down.
0.07	l	20	Lbl	beavertail cactus	Opuntia basilaris var. basilaris⁺	/	4
0.07	l		Lbl	Engelmann's hedgehog cactus	Echinocereus engelmannii	/
0.07				Jct with cross-sidewalk. Sign ahead: "Edith Meyerson Nierenberg Plaza dedicated 1996". Turn left toward Visitor Center.
0.08	r	21	Lbl	California trixis	Trixis californica var. californica	/	1
0.08	r		Lbl	ironwood	Olneya tesota⁺	/
0.09				Bicycle racks on right; bathrooms on left.
0.10	r		Lbl	silver cholla	Opuntia echinocarpa⁺	/
0.10	r		Lbl	ocotillo	Fouquieria splendens ssp. splendens⁺	/
0.10				Visitor Center entrance on left; map of immediate vicinity on right.
0.12	r	22	Lbl	elephant tree	Bursera microphylla	/	1
0.13	r		Lbl	creosote bush	Larrea tridentata	/
0.13	r			Sign: "Desert pupfish sanctuary" next to shallow pond with pupfish.
0.13	r		Lbl	indigo bush	Psorothamnus schottii	/
0.13	r	23	Lbl	California fan palm	Washingtonia filifera	/	1
0.14	r	24	Lbl	catclaw	Acacia greggii	/	1
0.14	r	25	Lbl	smoke tree	Psorothamnus spinosus	/	1
0.15	l			Jct. sidewalk connecting to Bridge Overloop sidewalk.
0.15	l		Lbl	California barrel cactus	Ferocactus cylindraceus var. lecontei⁺	/
0.15	r		Lbl	chuparosa	Justicia californica⁺	/
0.15	l	26	Lbl	desert lavender	Hyptis emoryi	/	1
0.15	r		Lbl	blue palo verde	Cercidium floridum ssp. floridum⁺	/
0.15	r			Jct. Nature Loop Trail. Sign: "Nature Loop Trail 0.25 mile loop; Campground 0.6 mile".
0.15				End of this guide at the junction with the beginning of the loop at mile 0.01.

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Copyright © 2003 by Tom Chester and Jane Strong.
Permission is freely granted to reproduce any or all of this page as long as credit is given to us at this source:
http://tchester.org/sd/plants/guides/anza_borrego/vc.html
Comments and feedback: Tom Chester | Jane Strong
Last update: 3 November 2003.