By Tom Oberbauer
Back when I was a student at San Diego State University working on my Bachelors and then Masters degrees in science, I spent a lot of time at the library. Keep in mind that the internet was not even a glimmer in anyone’s eye at that time. If the document you were searching for was not in the library, you had to search down some other library and ask for a loan or visit that library. The journals and other periodicals and books were the only sources for information that were readily available. However, keeping one’s nose to the grindstone could not be done all the time, so occasionally, I would explore books to find photographs of birds and plants. A magnificent set of books was the McGraw Hill set of the Wildflowers of the United States edited by H. W. Rickett of the New York Botanical Garden. It broke up the United States into areas, and had multiple volumes for each area with spectacular photographs and text. San Diego County was included in the three volume Southwestern States which included Southern California, southern Nevada, and Arizona and New Mexico. I had already acquired a copy of the initial Inventory of the Rare and Endangered Plants of California by CNPS and was interested in finding rare plants. However, when examining part three of the volume on the Southwestern States, I came across a photo of Acanthomintha ilicifolia (San Diego thornmint) on page 545.
For some reason, after seeing that photo, I became obsessed with finding that plant. I researched the address and wrote a letter to the photographer of the Acanthomintha photo that was in the book and she indicated that it was found in the area east of Chula Vista, which I thought at the time must be covered with houses. I reviewed over and over the text in Ethyl Bailey Higgins’ annotated checklist of plants of San Diego County so that I thought I had an idea of the habitats it preferred. I spent days hiking around the upper edges of canyons in Del Cerro and nearby areas searching for it, to no avail. I hiked around the slopes on Poser Mountain east of Alpine searching for it, and finally, as an unfunded and frugal student, I published a note in the CNPS-SD newsletter that I would pay a reward for anyone who found it and would let me know where I could see it. Unfortunately, that effort was unsuccessful as well.
However, I grew up in the area east of El Cajon called Singing Hills. McGinty Mountain was a major peak in the view from my grandmother’s house and I spent many mornings riding my bicycle down to Singing Hills Golf Course and hiking up the mountain to explore. McGinty Mountain is a treasure trove of rare plants with Nolina interrata (Dehesa beargrass), Clinopodium chandleri (San Miguel savory), Tetracoccus dioicus (Parry’s tetracoccus), and Monardella hypoleuca ssp. lanata (Felt leaf monardella) as a few. On top of the mountain is a large trench where feldspar was mined for making ceramic material. As I was exploring the upper ridge area of the trench on a day in May, I stumbled across a small patch of Acanthomintha plants that were nearing the end of their flowering season. Later, I found it farther down on the mountain in a clay lens that traversed the mid mountain trail. There is something about it’s small, purple and white flowers and the strange odor that it generates that is like a cross between the scent of a smashed Argentine ant, and mint, that makes it of special interest to me.
Since then, Acanthomintha ilicifolia has been found at a number of locations in San Diego County and I have seen it numerous places, including in northern Baja California, in locations where it may no longer exist, and an enormous population near Slaughterhouse Canyon in Lakeside. I still think it is a fascinating plant and I go and observe it whenever possible.
Acanthomintha ilicifolia is an ephemeral plant in the mint family. It grows generally less than a foot tall but some plants in favorable locations during favorable seasons may grow even taller. The leaves, when germinating, are distinctive with reddish coloration on otherwise green, semi-serrate, and deeply veined. At the other end of its growth cycle, it dries with a very characteristic skeleton. It has rounded bracts below the inflorescences that have pointed spines protruding around their edges. The stems dry to a straw color and the bracts remain in a bleached straw color as well, creating a mini forest of bract-clustered stems. In addition, the plants maintain the unique odor that can be released if the bracts are pressed between one’s fingers while avoiding being stuck with the thorns. However, the old skeletons decay rather quickly during the subsequent rainfall season.
Acanthomintha ilicifolia has generally been found on clay soils, mostly on hillsides and mesas, especially in Baja.
California, and in one location, near vernal pools. It is highly sensitive to rainfall levels and in some seasons, its numbers are very low due to low and irregular precipitation. It is listed as an endangered species by the Federal U. S. Fish and Wildlife Service since 1998 and the California Department of Fish and Wildlife since 1982.
I have often looked at the slopes of Viejas Mountain from afar, and from driving past on Interstate 8. I wondered about the large grassy patches that appear almost to be tilted terraces with a uniform flattened surface that slopes upward, and thought that they must be great locations for Acanthomintha. I have hiked up the trail Viejas Mountain, but it generally passes up the slopes away from the terraces that I saw from the freeway.
In the late spring of 2020, I participated in surveys financed by the San Diego Association of Governments (SANDAG), for monitoring of Acanthomintha on the lower slopes of Poser Mountain. These surveys are part of the regional programs to monitor and manage the rare and endangered species of plants and animals in San Diego County. The 2020 rainfall season was favorable for San Diego County and we found good numbers of them in flower. It turns out that the area of Poser Mountain that I explored decades ago was too high on the mountain. The good patches were down below Viejas Grade rather than above it which is where I had explored it.
Another location that needed to be surveyed in 2021 was the very slopes on Viejas Mountain that I wondered about for many years. I did not expect that it would be very fruitful because the 2021 rainfall season was disappointing, but the rain that did fall came at times advantageous for the plants, so one never knows what will be found until the area is examined in person.
I was scheduled to meet Diana Brand Ramirez from AECOM and Lauren Quon from the Cleveland National Forest by the Viejas Casino and then we drove to the end of Fazio Road. An old vehicle trail goes north from there, but it is very rutted and suitable only for walking.
We immediately started out in Chamise chaparral dominated by Adenostoma fasciculatum (Chamise), walking along the top of a low ridge with a moderately deep canyon to the east. The canyon had full on Riparian Oak Woodland with Quercus agrifolia (Coast live oak), Platanus racemosa (California sycamore), and a few Quercus engelmannii (Engelmann oak).
Since this was the lower slope of Viejas Mountain, the soil was derived from gabbro, a black granitic rock, that contains a high level of magnesium and iron, and weathers into clay in favorable sites. Gabbro supports many rare species of plants, but the clay soil is the part that fits our survey areas.
Gabbro has a tendency to affect shrubby plant growth so that it has spaces between the shrubs, making it easier to walk through it to a degree, and in this location, open areas along the trail also supported the typical chaparral transition and dry chaparral associates such as Eriogonum fasciculatum (California buckwheat), Salvia apiana (White sage), Baccharis sarothroides (Chaparral broom or Broom baccharis), Eriophyllum confertiflorum (Yellow yarrow) and Hazardia squarrosus (Sawtooth goldenbush). Other plants included Stylocline gnaphaloides (Everlasting nest-straw), a low growing, fuzzy leaved plant, and the bright yellow flowered Deinandra fasciculata (Fascicled tarplant), though low in number in this dry year. In previous seasons, the area has also been home to Acanthomintha ilicifolia, but we did not find any there.
However, our main goal was to get ourselves up on top of the high slope five hundred feet higher to our east to gain access to the large grassy areas. We were searching for any sign of a trail that headed up that way. Somehow, we convinced ourselves that a faint trail that broke off to the east was an appropriate route to take because the slope above was not as steep as other potential routes appeared to be. We dropped down into the canyon to the east and scrambled under large Heteromeles arbutifolia (Toyon), Quercus berberidifolia (Scrub oak), Ceanothus leucodermis (Chaparral whitethorn) shrubs, Xylococcus bicolor (Mission manzanita) and Rhus ovata (Sugarbush), crossing the drainage and pulling ourselves up the other side, grabbing shrubs and stepping carefully to keep from falling back down into the ravine. We attempted to find a way that followed shallow ridges rather than cutting up the steeper, more heavily vegetated slopes, but we ended up climbing through the heavy parts anyway.
I should mention that we wear protective gear when out in the field; long pants, snake guards, hiking boots, long sleeve shirts and gloves. The gloves help protect your hands from getting ripped up when grabbing for branches and when needing to crab crawl up a slope that is too steep to walk. I have been a firm believer in wearing snake guards for many years particularly while performing cross country surveys due to encountering rattlesnakes so many times as they buzz beneath rocks and shrubs or pass nearby. This was further emphasized a couple of years ago when I was walking on a narrow rabbit trail along State Route 52 near Santee. It was a cool, spring morning as I was walking quickly on the trail that had a variety of broad leaf annuals, clovers and lupines, growing over it when I stepped on something squishy. As I quickly looked back behind me, I saw a flash of the form of a snake. I wasn’t sure what kind when I first glimpsed it, but I quickly stepped away and stopped, observing that it was a medium sized Crotalus viridus (Pacific rattlesnake). I was not sure if I mortally wounded it with my step. It did not strike and did not buzz. I think I stepped on the central part of its body. The really disturbing part for me was the feeling of its body rolling under my boot. It lay still for a few minutes, but then slithered away. I should consider myself lucky that it did not strike, but I came upon it faster than it could react in the morning that was warming yet still cool. I was wearing strong leather boots with the snake guards that come down over the tops, so that if it did strike, it would have hit the guards anyway.
Eventually, we were able to get up onto a more consistent climbing slope that was covered by many of the shrubs mentioned, but also Salvia mellifera (Black sage) in the less dense areas. The slope was very steep and the soil a bit unstable but additional species included Brickellia californica (California brickellbush), Ceanothus perplexans (Cupped leaf ceanothus), Eriodictyon crassifolius (Felt leaved yerba santa), Salvia apiana (White sage), and Cneoridium dumosum (Coast spicebush) with its skin marking properties. However, it wasn’t all medium to large sized shrubs. There were also smaller plants of interest including Porophyllum gracile (Odora) with its small, gray stems that always raise the question of whether or not its odor is offensive, Lupinus hirsutissimus (Nettle lupine) on areas with open soil, Malacothamnus fasciculatus (Bush mallow) with rounded, felty leaves, the small growing Mirabilis laevis (Wishbone bush) that has dark pink flowers growing in little mounds, Oxalis albicans (California wood sorrel), a light yellow flowered native oxalis, and Galium angustifolium (Narrow leaf bedstraw). After leaving the heavy vegetation, the climbing became much easier, just steep climbing and carefully watching one’s step. A trip would mean bouncing downhill at worst and falling backward into scratchy shrubs at best.
Eventually, the slope broke and we emerged on top of the ridge and tilted plateau. A strip of chaparral still separated us from the grassy plain area and it was dominated by Chamise but including interesting species such as Trichostemma parishii (Mountain bluecurls), and a few Salvia clevelandii (Cleveland sage) that announces its presence a long distance from its actual location by its, sweet, laundry soap scent. The grassy area was about a tenth of a mile wide and a quarter of a mile long, tilted up slope. The vegetation changed significantly. While shrubs were still scattered around, the open clay slopes were covered with a diverse mix of annuals and herbaceous perennials that included Ambrosia psilostachya (Western ragweed), Deinandra fasciculata, though still not in great numbers, Eriophyllum confertiflorum, a few Lasthenia gracilis (Goldfields), Corethrogyne filaginifolia (Sand aster), a few Amsinckia menziesii (Rigid fiddleneck), Acmispon glaber (Deerweed), some small patches of Lupinus bicolor (Miniature lupine), Clarkia purpurea (Purple clarkia) in low numbers, California peony (Paeonia californica), small patches of the tiny Plantago erecta (Dot-seed plantain), Allium haematochiton (Red-skinned wild onion) which actually smells more like garlic, Chlorogalum parviflorum (Soap plant, Amole), Sisyrinchium bellum (Blue eyed grass) a few Calochortus splendens (Splendid mariposa lily), Bloomeria crocea (Common goldenstar), and Dipterostemon capitatus (Wild hyacinth) that has suffered another change in scientific name. The shrubs that crept over and appeared in scattered locations as individuals and small patches included Baccharis sarothroides, Salvia apiana, Eriogonum fasciculatum, Rhamnus crocea (Redberry), Adenostoma fasciculatum, Heteromeles arbutifolia and the Hesperoyucca whipplei (Chaparral candle).
Salvia sonomensis (Creeping sage) is also found on the terraces and upper slopes of Viejas Mountain. It is a unique salvia for several reasons. It grows along the ground and produces pretty blue flowers, but its range is particularly interesting since it is found in Central California down to Santa Barbara County and nowhere in between except one spot in the San Gabriel Mountains at a helipad, but it is quite common in the eastern foothills of San Diego County.
Of course, the major presence in this grassland, herbland was a group of native and non-native grasses. The native grasses included Stipa lepida (Foothill needlegrass), Melica imperfecta (Coast range melic), Aristida adscensionis (Sixweeks threeawn) and Vulpia octoflora (Slender fescue). The non-natives included the weedy grasses that are found many locations including Avena fatua (Wild oat) and Avena barbata (Slender wild oat), Bromus madritensis (Red brome), Bromus hordeaceous (Soft chess), and the scourge, Brachypodium distachyon (Purple falsebrome) that has taken over clay soils and other grassy areas in the past decade or more. It is especially problematic because it likes habitat for Acanthomintha ilicifolia.
At this point, we began to search in earnest for Acanthomintha. Fortunately, we also had data on digital maps from previous seasons to serve as a basis. The thing that was amazing to me was that we began to find them. I had presumed that due to the half normal precipitation level that the numbers would be few and plants would be far between. Once we began to find them, we started seeing good numbers of them. Most were not flowering yet, but they appeared to be generally in good enough condition that they would mature into flowering plants. We did find a number of them that were in full flower and were of moderate size for Acanthomintha. As we began to scour the sloping grassy terrace, our goal is always to find new populations that have not been seen before or at least not documented previously. However, since we make manual counts and estimates based on those counts, we were finding hundreds of them in individual populations, and thousands over extended areas of subpopulations. We were pleasantly surprised that we found all of the known populations and a couple of additional ones and that there were so many of them this year.
We began our trek back down. We were farther north than the slope we had climbed, and looked for a way down while avoiding the various ravines that crossed the bottom of the slope. We figured if we went down a bit farther north than we came up, we would be able to avoid the ravines altogether. However, it was even more steep than the way we came up. We walked gingerly down slope, having to grab onto the slope and trusting in sturdy plants for balance. The slope was a little slippery as well composed of a decomposing feldspar rich material.
The route we took passed near a cluster of Nolina cismontana (Chaparral beargrass), yet it was far enough away that we did not take the time to examine it. Nolina interata (Dehesa beargrass) is found on gabbro soils in southern San Diego County southward to near Valle de Guadalupe in Baja California. Nolina cismontana was described by Jim Dice for the plants that occur on gabbro soils on Viejas Mountain and along Magee Ridge, north of Pala and into Orange County and even Ventura County. Both are bushy monocots with long, strap shaped leaves and large inflorescences that shoot skyward. Nolina interata is glaucus gray in color and has an underground root mass while Nolina cismontana’s root mass is above ground and is greener in appearance. Unlike Nolina cismontana, Nolina parryi has narrow leaves and prefers a desert habitat. Viejas Mountain is the southernmost location for Nolina cismontana.
After a long time of steep, downward steps, we were finally able to stumble our way down to the flatter land below and back to the cars. We were quite pleased that we were able to find so many of the Acanthomintha plants that particular year.