This section contains entries about our botanizing in Baja California written for the UC BEE (Oct 2012 to Aug 2021)
and The UC Hive (2022-), monthly newsletters for volunteers and staff of the UC Berkeley Botanical Garden.
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THE HIVE MAR 2025
In organizing my photos from last year, I realized I had completely forgotten about the field trips I made last Spring, as well as my return trip to the US. So this month, I've prepared a few photos of my field trip in early May to San José de Magdalena, located about 45 minutes northwest from Mulegé. I've written about this area several times in the UC Bee (Apr 2013, Jun 2015, May 2021) because it is such an amazing place, with beautiful landscape, natural freshwater pools surrounded by native vegetation, and friendly residents. Oh, and let's not forget their major export: GARLIC!
The water crossing just before town changes depending on the amount of water that comes down the arroyo. This year, lots of plants were thriving along the banks as there had been no flooding in the summer.
The town has a number of interesting older buildings, like this slowly crumbling adobe. It used to have a palm roof. There are other historic buildings made of fired brick, possibly made from local materials.
Once out of the arroyo bottom near town, the road climbs up to a dry hillside. View of old palm orchards below, near the bottom.
The Desert Ironwood were very much in bloom as well as on the hills leading up to town from the highway.
Organpipe Cactus (Stenocereus thurberi) with buds.
Organpipe Cactus with a flower showing young fruit.
These Butterfly Vine fruit when dry will be papery and tan and vaguely resemble butterflies.
Another Desert Ironwood tree profusely blooming.
Desert Ironwood with buds, open flowers and bees.
Sandpaper Plant (Petalonyx linearis). This plant is about 80 cm D x 60 cm H. All of the herbage is rough and velcro-like.
The tiny 5-petalled flowers, about 5 mm D, are borne in the leaf axils. Another species in Loasaceae with velcro-like or prickly hairs.
The honeybees were active on the Little-leaf Palo Verdes (Parkinsonia microphylla) early in the morning as I headed up the hill from the highway.
Now that I am tuning in to lichens, I wonder about the dark spots on the white bark of this Palo Blanco (Lysiloma candidum). Hmm...I need to revisit it.
Palo Blanco. The blue-green compound leaves have 1-3 pairs of pinnae & 2 leaflike stipules. The creamy inflorescences are c. 2 cm D.
The watercrossing west of town where I spent several hours taking photos and vouchering specimens. It was lush with vegetation.
The salverform flowers of Doctorbush (Plumbago zeylanica) are c. 1.5 cm D with glandular hairs on the calyx and blue anthers. I´ve observed this individual for years.
Pink flower of Slimjim Bean (Phaseolus filiformis) with its lime green corkscrewed keel petal, and Sweetbush (Bebbia juncea var. juncea) on the drier section of the river crossing.
The wide stream seen in the previous photo is barely visible through the dense thicket lining it. Foreground: Eucnide cordata. Some of the taller plants in the middle range are willow (Salix sp.)
Two species of Solanum. The large flower & gray-green leaves belong to S. hindsianum (Baja California Nightshade) while the dark green leaves & tiny flower below are S. douglasii.
Douglas' Nightshade (Solanum douglasii) is a perennial herb or subshrub up to 2 m H. The corolla is 13-15 mm D, deeply lobed and gen. has green spots at the base of the lobes.
The herbage of Douglas' Nightshade has minute, white, non-glandular hairs. The fruit (a berry) is 5-10 mm D and the black, mature fruit gen. remains on the plant.
Brandegee Brickellbush (Brickellia brandegeei). Flowers in this genus are discoid (i.e., they lack ray florets).
Identification is determined by leaf shape and sepal characteristics, as well as the degree to which the stamens are exserted.
Sonoran Passion Flower (Passiflora pentaschista) gave form to much of the thicket along the river, binding the other species together. Most was completely impenetrable.
Flower of Sonoran Passion Flower withering under the sizzling May midday sun.
Castor Bean (Ricinus communis) is a hearty herbaceous weed that dominates in riparian habitats like this one. Many can reach heights of 6 m or more.
Castor Bean is monoecious. The red flowers are pistillate, with a bristly ovary. The whitish staminate flowers are below. The lower buds are also staminate.
A drying fruit is visible; it will split into three sections, each with a single seed that will be forcefully ejected at maturity.
A part of the bristly Castorbean pod. The seeds pictured are c. 10 mm L. They are highly toxic when ingested.
When I first saw the mature seeds of Ricinus a few years ago scattered over a sandy area along the Mulegé river bank, I thought that they were either beetles or bugs. A closer looked at their shiny, mottled surface revealed their true nature. The seed has a spongy caruncle on one end which will absorb water and help the seed to germinate. .
They are certainly well camouflaged on rocky soil or amongst leaves and other debris. In writing this entry, I learned that "the word ricinus is Latin for 'tick', used for this plant name because of the superficial resemblance of the seeds to a particular species of European tick" [1].
The flowers of Tephrosia palmeri are 20-25 mm L and are borne on a long raceme, often well above the plant.
The herbage and lower surface of the petals of Palmer Hoary-pea are finely and densely pubescent, giving it a gray-green appearance.
The long, narrow beans of Palmer Hoary-pea, like many members in the Pea family, are explosively dehiscing, ejecting the small, flat, rectangular seeds far & wide.
I had a fantastic time collecting along the river bank, but regrettably was finally forced to stop, not only because I was overheating in the early afternoon sun, but because I had completely run out of cardboard and newspaper for the press, and all of the plastic bags, shopping bags and a bucket that I just happened to have left in the car were stuffed with cuttings wrapped in damp paper towels or newspaper. I had collected enough material for 42 vouchers of 15 taxa. I had also made brief phenology notes for 53 taxa, knowing that there were many more that were present that I hadn't the time to record.
My latest project has been to collect vouchers from as many different taxa as possible from San José de Magdalena while on our visits to the area, much like how I had begun with my checklist of Mulegé plants. While the area hosts many of the same taxa as Mulegé and Bahía Concepción, because of its elevation above 200 m and the presence of fresh water streams and pools along the arroyo bed, it also has elements of the flora of the Sierra de la Giganta ecoregion.
The press after prepping the day's collections which would result in 42 vouchers for 15 taxa.
That's it for now. Next entry, I plan to have more about some of last year's field trips. In mid March a geologist and I will be leading a tour at Punta Chivato, so hopefully I'll have a report on that to share in the near future. Hasta pronto...see you soon.
Debra Valov — Curatorial Volunteer
References and Literature Cited
Rebman, J. P., J. Gibson, and K. Rich, 2016. Annotated checklist of the vascular plants of Baja California, Mexico. Proceedings of the San Diego Society of Natural History, No. 45, 15 November 2016. San Diego Natural History Museum, San Diego, CA. Full text available online.
Rebman, J. P and Roberts, N. C. (2012). Baja California Plant Field Guide. San Diego, CA: Sunbelt Publications. Descriptions and distribution.
[1] University of Wisconsin (2025). Castor Bean, Ricinus communis. Available at: https://hort.extension.wisc.edu/articles/castor-bean-ricinus-communis/ Accessed 25-Feb-2025 [back to text]
Valov, D. (2020). An Annotated Checklist of the Vascular Plants of Mulegé, Baja California, Mexico. Madroño 67(3), 115-160, (23 December 2020). https://doi.org/10.3120/0024-9637-67.3.115
Wiggins, I. L. (1980). The Flora of Baja California. Stanford University Press. Keys and descriptions.
