San Diego Natural History Museum Botany Department

San Diego Natural History Museum Botany Department Adventures with the native and naturalized plants of southern California and the Baja California peninsula!

Our SDNHM Curator of Botany, Dr. Jon Rebman, is giving a general talk tomorrow for the Cactus & Succulent Society of Ame...

Our SDNHM Curator of Botany, Dr. Jon Rebman, is giving a general talk tomorrow for the Cactus & Succulent Society of America entitled "Baja California: botanical research and succulent diversity" that is open to the public. Feel free to join if you have the time and interest in this topic!

CSSA Webinar Saturday, March 20th at 10:00 am PDT
Jon Rebman: The Flora of Baja California.

Everyone is welcome:

The Baja California peninsula and its adjacent islands support a wealth of species diversity in many different plant families. There are approximately 4400 different plants, of which 26% are from (endemic to) the region.

Dr. Rebman has been involved in various expeditions to remote parts of the Baja California region and its adjacent islands. During these trips, some significant botanical discoveries have been made that impact our knowledge of the plants in these regions and provide us with new ideas on plant biogeography in desert areas of our region.

Photos from San Diego Natural History Museum Botany Department's post

Photos from San Diego Natural History Museum Botany Department's post

Tree To***co (Nicotiana glauca)Potato/Nighshade Family (Solanaceae)Family info: Solanaceae: The family Solanaceae includ...

Tree To***co (Nicotiana glauca)

Potato/Nighshade Family (Solanaceae)

Family info: Solanaceae: The family Solanaceae includes approximately 75 genera and 3000 species with a worldwide distribution, especially diverse in tropical regions of South America. Members of the Solanaceae are herbs, shrubs, trees, or vines with usually alternate, simple or compound leaves, and typically small, whitish flowers arranged in a panicle that produce a capsule or drupe. The family contains many economically important members, including edible species such as peppers (Capsicum), tomatoes (Lycopersicon), and potatoes (Solanum); species with drugs like to***co (Nicotiana) with ni****ne or Belladonna (Atropa belladonna) with atropine; and garden ornamentals such as petunias (Petunia). Alkaloids are present in many species in this family and some species are deadly poisonous or contain known carcinogens.

Genus info: The genus Nicotiana contains approximately 60 species, mostly in the Americas, of annual or perennial herbs or shrubs to small trees with alternate, mostly simple leaves. The flowers have funnel-shaped to salverform corollas with 5 stamens and produce dehiscent (splitting) capsules that contain many small, angled seeds. Most species have ill-smelling herbage and indigenous peoples reportedly smoked some species. The entire genus is poisonous to some degree and contains economically important species such as the to***cos of commerce (N. tabacum and N. rusticum) and various garden ornamentals. Six species of Nicotiana are known to occur in San Diego County. The genus name is from J. Nicot, who supposedly introduced to***co to Europe.

Species info: Tree To***co is an introduced w**d from northwestern Argentina and southern Bolivia that has naturalized in many habitats throughout our region and in other warm regions of the world. It is a glabrous, erect, sparsely branched shrub or small tree to 5 m tall with 5–16 cm long ovate, bluish-green, glaucous leaves. The tubular, cylindric, yellow to yellow-green flowers are 3–4 cm long and bloom throughout the year. The fruit is an ovoid capsule, that dehisces with 4 valves releasing many reddish-brown seeds. It is sometimes seen planted around houses, furnishing meager shade but requiring little care or water. Tree To***co attracts hummingbirds but repels livestock and is deadly to insects. This species has been used to treat rheumatism. The entire plant, especially the leaves, contains anabasine, a close relative of ni****ne, and has caused poisonings and even deaths to humans. The specific epithet glauca is from Greek and means "bluish-gray," and refers to the thin waxy layer or whitish powder (bloom) that is found on some plant parts, especially the leaves. This species is native to South America, but has naturalized extensively in the southwestern and southeastern USA, Mexico, Africa, and the Mediterranean region.

Here are some pics taken by SDNHM Curator of Botany, J. Rebman, in January 2021 in a couple of our local urban canyons i...

Here are some pics taken by SDNHM Curator of Botany, J. Rebman, in January 2021 in a couple of our local urban canyons in San Diego. There is a lot of native botanical diversity in these canyons between neighborhoods and also many non-native plants that have naturalized there.

Crystalline Iceplant (Mesembryanthemum crystallinum)Fig-Marigold Family (Aizoaceae)Family info: Aizoaceae: The well-know...

Crystalline Iceplant (Mesembryanthemum crystallinum)
Fig-Marigold Family (Aizoaceae)

Family info: Aizoaceae: The well-known leaf-succulent family Aizoaceae is represented in our region primarily by exotics known as iceplants (Mesembryanthemum and Carpobrotus spp.). However, a few native species, such as in the genera Sesuvium and Trianthema can be found in San Diego County. The large and diverse Fig-Marigold family contains 130 genera and approximately 2500 species worldwide, but in our County only 17 species have been documented and most of these have escaped from cultivation and are native to southern Africa. The dry, dehiscent fruits of many species in this family respond to moisture and are closed when dry, but during wet conditions they open to release the seeds. The showy, linear, petal-like structures found in the flower of many members of this family are actually staminodes (modified and sterile stamens of the flower).

Genus info: According to Michael Charters website ( on plant names for California the genus name is “either derived from (1) two words: mesos, "middle," and embryon, "fruit," indicating a flower with its fruit in the middle, and/or (2) afternoon-blooming. The original name was Mesembrianthemum, from mesembria or "mid-day" alluding to the belief that the species only bloomed in the sunlight. After night-blooming species were discovered, the spelling of the name was changed to its current form”. Some of these naturalized exotics are very aggressive w**ds, such as the widespread, annual species of Mesembryanthemum, which can take over large tracts of disturbed habitat and accumulate and release salts into the soil, thus eliminating other plants from growing in the area.

Species info: Crystalline Iceplant is a nonnative, low-growing annual or biennial with succulent, ovate to spatulate leaves to 20 cm long that are covered with large bladdery cells. These inflated cells give the plant a glistening appearance, like ice covering its surface, hence the common name “iceplant.” When stressed or with age, the whole plant commonly turns reddish in coloration; this can be seen easily in some coastal flats or beaches in our County where this species has invaded en masse. Crystalline Iceplant occurs mostly on the immediate coast in our region, but occasionally it occurs further inland in disturbed, saline habitats.

Observation of the Month: Alligatorw**d (Alternanthera philoxeroides) Amaranthaceae
Alligatorw**d (Alternanthera philoxeroides)

Observation of the Month: Alligatorw**d (Alternanthera philoxeroides) Amaranthaceae by chrysaetos

It’s on the official list of California noxious w**ds, so the discovery of Alligatorw**d (Alternanthera philoxeroides) in San Diego County was not welcome news. The observation posted by Jorge Ayon (@chrysaetos) a few months ago brought the plant to the attention of Jon Rebman and with Jorge’s assistance, he obtained a voucher specimen to confirm the identification and document the plant’s presence in our county. Early detection of invasive species such as Alligatorw**d is important to allow land managers to gain control of the population before it grows to the point where it cannot be eradicated locally and before it spreads to other locations.

Alligatorw**d can form dense floating mats when it invades lakes, ponds, streams, and irrigation ditches. It is native to South America. According to Cal-IPC, it was introduced in California when it was previously used in the aquarium trade. Efforts are underway to eradicate it in the San Joaquin Valley and Sacramento Delta areas.

The leaves of Alligatorw**d are elliptic, less than an inch wide and 5 inches long, and are opposite with entire margins. The inflorescence is spherical about ½ inch in diameter with papery white flowers. Outside its native range, Alligatorw**d is not known to produce seeds, but it still reproduces and spreads very easily by vegetative fragments.

Alligatorw**d from Lower Otay Lake, Jamul, CA, US on September 03, 2020 at 07:07 PM by chrysaetos

Here are some plant photos taken by J. Rebman in December 2020 at Horsethief Canyon in San Diego County. This area was b...

Here are some plant photos taken by J. Rebman in December 2020 at Horsethief Canyon in San Diego County. This area was burned in the Valley Fire in September 2020 and many of the plants are starting to regenerate after this wildfire.

Join Dr. Jon Rebman, SDNHM Curator of Botany, tomorrow evening for a virtual presentation entitled "Plant Rediscoveries ...

Join Dr. Jon Rebman, SDNHM Curator of Botany, tomorrow evening for a virtual presentation entitled "Plant Rediscoveries in Baja California and Discoveries in San Diego" hosted by the San Diego Chapter of the California Native Plant Society (CNPS). Here is the link and info on how to listen in:

Here are a few plant pics taken in December 2020 by J. Rebman, SDNHM Curator of Botany, in San Diego County.

Here are a few plant pics taken in December 2020 by J. Rebman, SDNHM Curator of Botany, in San Diego County.

Puncture Vine (Tribulus terrestris)Caltrop Family (Zygophyllaceae)Species info: This uncommon non-native prefers disturb...

Puncture Vine (Tribulus terrestris)
Caltrop Family (Zygophyllaceae)

Species info: This uncommon non-native prefers disturbed habitats like vacant lots, along roads, sidewalks, etc. and is especially common in urban habitats. The species is native to the Mediterranean region, but has been introduced and has naturalized in much of the USA, Canada, Mexico, and Central & South Americas. It has many various common names such as Puncture Vine, Caltrop, and Goathead, all referring to the very spiny fruits that break apart into individual nutlets that easily puncture a bike tire or painfully pe*****te a bare foot or hand. The specific epithet terrestris means “on land” and it is one of those w**dy species you should be wary of when crossing any land.

Genus info: According to M. Charters (, the genus name Tribulus is derived from the Greek tribeles or tribolos and Latin tribulus because of the three-spiked shape of the fruit which is similar to a caltrop, an ancient military weapon composed of an iron ball with projecting spikes that could be put on the battlefield to slow cavalry or soldiers.

Family info: Zygophyllaceae: The Caltrop family includes 22 genera and 285 species in tropical semiarid and desert regions of the Old and New Worlds. Most members are herbs or shrubs, rarely trees, with branches jointed at the nodes and opposite or alternate leaves with well-developed stipules and often compound leaves with paired or even-pinnately arranged leaflets. In ours, the flowers are usually solitary in leaf axils and have 5 sepals, 5 petals, and a nectary disk. The fruits are variable in this family, but most of our species usually have a dehiscent (splitting) capsule or a schizocarp that splits into separate nutlets. In San Diego County, the family Zygophyllaceae is represented by 4 genera and 6 species. Probably the best known member of this family in our region is Creosote Bush (Larrea tridentata), which is a dominant shrub in desert areas such as the Anza-Borrego Desert State Park.


1788 El Prado
San Diego, CA


Be the first to know and let us send you an email when San Diego Natural History Museum Botany Department posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Contact The Museum

Send a message to San Diego Natural History Museum Botany Department:



Other Museums in San Diego

Show All


Of course you want to know what wildflowers you found in the Anza-Borrego Desert State Park and surrounding area. We have a great website with high-resolution photos. Use our iOS or Android app as off-line field guide. This app is intended for the casual flower user and experienced botanist alike. Find plants by color, common name, scientific name or family name. The app includes keys, descriptions and many photo's of plant details.
Good work, Jon, John, and Jose! And thank you National Geographic, for your support of basic field work!