The Story of Arapejo Grass (Muhlenbergia utilis): Good Botanical Intuition Paying Off

IMG_6937Bronco Canyon Spring, home of Arapejo grass (Muhlenbergia utilis)

Today as I sit here planning this weekend’s fieldwork on Tejon Ranch I am contemplating the value of intuition in conducting plant surveys. This important characteristic of good field biologists was exhibited expertly this winter by Tejon Ranch Conservancy Conservation Science Director, Dr. Mike White. Back in early January Mike sent an email  to me, and couple of other botanists with pictures of a grass growing in a spring in the upper reaches of Bronco Canyon, on the southern side of the Tehachapi Mountains. His gut reaction was that the grass resembled saltgrass (Distichlis spicata), but that it did not look quite right.

grass3Muhlenbergia utilis, Arapejo grass, Photo by Mike White

I showed the email to Dr. Hester Bell, a postdoctoral research associate at RSABG, who studied Distichlis for her PhD dissertation. While the photos made it difficult to make a conclusive identification her first indication was that the plant was possibly just saltgrass.  Fast-forward a couple of weeks later in January, I a spent a day on the ranch with Mike checking on the phenology for the spring field season, during which we visited the spring in Bronco Canyon. When I inspected the plants growing in the spring I agreed that the plants did not look quite like saltgrass. Specifically, the leaves appeared to be too fine and the inflorescences seemed too small and delicate for that species.  Based on this assessment I decided to make a number of herbarium specimens, so that their identification could be determined back at the RSABG herbarium.

IMG_6950The view of the Antelope Valley from the Tehachapi Mountains above Canyon de la Lecheria

A week or so later when I showed the specimens to Hester, she exclaimed, “that’s not Distichlis.” After some time in the herbarium comparing the plants with other specimen, and in consultation with curatorial assistant, LeRoy Gross, we determined that the grass is Muhlenbergia utilis, commonly known as Arapejo grass.

IMG_6943Lupinus excubitus likely var. johnstonii, grape soda lupine, a rare plant collected in March

Arapejo grass is currently known from a very small number of populations in California: Big Springs in Inyo County, Red Hill near Upland in San Bernardino County (the site of a county park, population now extirpated), Murrieta Canyon in Ventura County, two Locations in San Luis Obispo County, and two locations on Tejon Ranch in Kern County (in March I collected plants at a new location southwest of Bronco Canyon). Arapejo grass is restricted to riparian, pond, and freshwater spring habitats in California, Arizona, Nevada, and Texas. While this species is not considered rare throughout its range, it is certainly very uncommon in California (six total occurrences). In addition, the collection of the species in the Tehachapi Mountains represents a regional range extension within California. Based on this information it is my opinion that Arapejo grass should be considered for addition to Rank 2B (plants rare in California, but more common elsewhere) of the CNPS Rare Plant Inventory.

IMG_6977Shannon Still, Eve Laeger, and Ed Kentner (left to right) enjoying the view and one of Tejon’s majestic oaks

This field season I am looking forward to searching for more populations of Arapejo grass on Tejon Ranch. Due to this year’s paucity of precipitation there will be no vast fields of annual wildflowers on the ranch. In particular, much of the low elevation habitat in the San Joaquin Valley (for example, the Tejon Hills) is already bone-dry and the current vegetation looks more like it should in August than in April. On a positive note, rain in February and March has led to quite a lot of germination of annual seedlings in the lower elevations of the Tehachapi Mountains, and the upper slopes of the Mojave Desert portions of the Ranch. In particular, the ranch has seen almost two inches of rain since last Friday!  This should ensure that the seedlings that have already germinated will be able to flower, and a good show of perennials at higher elevations later this spring and summer.

IMG_6938Dendromecon rigida, bush poppy

Furthermore, many of us are watching NOAA’s El Niño forecast for next fall and winter.  Currently, all models are pointing toward a 50% chance of an El Niño pattern developing this summer and fall, and have upgraded the El Niño Alert System Status to an “El Niño Watch.”  Should the El Niño climatic pattern come to fruition next winter could be wetter than normal and wildflower fields on Tejon so bright that sunglasses will be necessary.

Bronco springBronco Canyon Spring, the prominent grass is  Muhlenbergia rigens , deer grass (yes, another Muhlenbergia!)            Photo by Mike White


Only 1 comment left

  1. Katie Gallagher /

    Despite the paucity of precipitation, we still might get an excellent exhibition of Eriogonums.

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