CPC Plant Profile: Sandfood
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Plant Profile

Sandfood (Pholisma sonorae)

This unique little plant growing on a sandy bank near a highway exit ramp. Photo Credit: Kathy Rice
Description
  • Global Rank: G2 - Imperiled
  • Legal Status: N/A
  • Family: Boraginaceae
  • State: AZ, CA
  • Nature Serve ID: 146711
  • Date Inducted in National Collection: 02/10/1987

Pholisma sonorae is an obscure, parasitic plant with extremely strange attributes. The plants are gray and mushroom-shaped, and their height depends on the degree to which blowing sand covers the scaly stem (Armstrong 1980a). This succulent stem extends 1-2 m below the sand and is attached to roots of nearby host plants (Armstrong 1980a). The scales on the stem are actually modified leaves. Pholisma appears to be perennial (Yatskievych 1985), dying back to undifferentiated tissue at the infection site on the host plant every year. Incredibly, host plants do not appear to be depleted by Pholisma infestation and Pholisma plants have been unearthed and weighed, with the weights exceeding those of host plants. The inflorescences form the 'cap' of the mushroom-like plant, bearing numerous purple flowers arranged in a ring toward the outer edge of the cap. Each flower is surrounded by a hairy calyx and the masses together calyces give the inflorescence a gray-white fuzzy appearance, while protecting plants from sun and heat (Copeland 1935). Fruits are capsules having 12-20 tiny seeds, similar in size to the surrounding grains of sand. Stems of plants were historically eaten raw or roasted by native American tribes, such as the Sand Papagos and Cocopas (Castetter & Bell 1935, 1951; Thackery 1953).

Participating Institutions
Updates
  • 09/23/2020
  • Propagation Research

A small mass containing hundreds of seeds were sent to Dr. Valerie Pence at Cincinnati Zoo and Botanical Garden. Seeds had been sent previously in 1987, but they had been previously frozen for an undetermined amount of time. Dr. Pence conducted tetrazolium tests on the 1987 seeds and determined that they were non-viable. Information from G. Yatskievych (pers. com., 1993) about the nature of the undifferentiated embryo, and oily endosperm led Dr. Pence to believe that freezing may have permanently damaged the seeds.

  • 09/23/2020
  • Genetic Research

Alan Smith studied the phylogenetic relationship of Pholisma spp. using molecular data generated from field-collected specimens. The resulting analysis indicates that Lennoaceae is closely related to Boraginacese.

  • 09/23/2020
  • Propagation Research

Desert Botanical Garden is currently processing seeds by hand. Collected seeds from the 1998 lot have been hand-cleaned by volunteers and counted using an analytical balance. A small mass containing hundreds of seeds were sent to Dr. Valerie Pence at Cincinnati Zoo and Botanical Garden. Seeds had been sent previously in 1987, but they had been previously frozen for an undetermined amount of time. Dr. Pence conducted tetrazolium tests on the 1987 seeds and determined that they were non-viable. Information from G. Yatskievych (pers. com., 1993) about the nature of the undifferentiated embryo, and oily endosperm led Dr. Pence to believe that freezing may have permanently damaged the seeds. Germination experiments at the Garden using rootbound host plants were also conducted on Pholisma in 1993, but no seed germinated. A dissertation on Ammobroma sonorae germination requirements by Cothrun (1969) concluded that all known and experimental methods used to germinate seed of any plant were attempted, and no germination occurred. Seeds were recollected in 2000, and are still being cleaned. There has been a recent unverified report that seeds have been germinated in vitro.

  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 1 accessions of Pholisma sonorae in orthodox seed collection. There are as many as 9931 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

  • 08/05/2020
  • Seed Collection

Based on an August 2020 extract of the California Plant Rescue Database, California Botanic Garden has collected 1 seed accessions of Pholisma sonorae from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass an unknown number of maternal plants

Nature Serve Biotics
  • 05/02/2017

A moderately widespread but rare parasite, known from southwestern Arizona along border with Mexico east of San Luis, southeastern California (Imperial County), northwestern Sonora and northeastern Baja California, Mexico. ""Widespread in Gran Desierto and a few locations in Arizona but low numbers within each occurrence."" (Laurenzi and Spence 2012).

Kathleen C. Rice
  • 01/01/2010

Current threats to Pholisma include development (conversion of dune habitat to housing and agricultural land), and off-road vehicle use. The Imperial and Algodones dunes are located primarily on BLM lands, and although a small section of habitat has been

Kathleen C. Rice
  • 01/01/2010

Only two populations are known from California and Mexico. A site documented by a herbarium specimen on U.S.-Mex. Hill was visited during 1998, and no plants were located. As the site is rather remote and undeveloped, it appears that dune stabilization by associated species has sufficiently altered the habitat to the extent that Pholisma sonorae can not grow there. Two years ago, Pholisma was located near a lemon grove, at a site documented by a herbarium specimen made by Jepson. South of the U.S.-Mexican border, far more sand dune habitat can be found, but the status of the plants is unknown for that area.

Kathleen C. Rice
  • 01/01/2010

Desert Botanical Garden is currently processing seeds by hand. Collected seeds from the 1998 lot have been hand-cleaned by volunteers and counted using an analytical balance. A small mass containing hundreds of seeds were sent to Dr. Valerie Pence at Cincinnati Zoo and Botanical Garden. Seeds had been sent previously in 1987, but they had been previously frozen for an undetermined amount of time. Dr. Pence conducted tetrazolium tests on the 1987 seeds and determined that they were non-viable. Information from G. Yatskievych (pers. com., 1993) about the nature of the undifferentiated embryo, and oily endosperm led Dr. Pence to believe that freezing may have permanently damaged the seeds. Germination experiments at the Garden using rootbound host plants were also conducted on Pholisma in 1993, but no seed germinated. A dissertation on Ammobroma sonorae germination requirements by Cothrun (1969) concluded that all known and experimental methods used to germinate seed of any plant were attempted, and no germination occurred. Seeds were recollected in 2000, and are still being cleaned. There has been a recent unverified report that seeds have been germinated in vitro. Alan Smith studied the phylogenetic relationship of Pholisma spp. using molecular data generated from field-collected specimens. The resulting analysis indicates that Lennoaceae is closely related to Boraginacese.

Kathleen C. Rice
  • 01/01/2010

Within the U.S boundaries, management for conservation of Pholisma sonorae is occurring in California on BLM land designated as off-limits to ATV recreational use. Elsewhere, the species is not protected.

Kathleen C. Rice
  • 01/01/2010

Management needs are incredibly challenging, as dunes must remain unstabilized in order for Pholisma to persist. Increasing conversion of these dunes to agricultural fields, housing developments, highways, and recreational sites will hasten the extinction of Pholisma sonorae.

Kathleen C. Rice
  • 01/01/2010

Ex situ needs are equally as challenging as management problems. Since seeds do not germinate reliably, and no means of perpetuating them in cultivation has been found, the species does not lend itself readily to ex situ conservation. For this particular species, in situ conservation efforts are the key to perpetuation.

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Photos
Nomenclature
Taxon Pholisma sonorae
Authority (Torr. ex Gray) Yatskievych
Family Boraginaceae
CPC Number 3407
ITIS 504335
USDA PHSO
Common Names Sand Food | Sandfood
Associated Scientific Names Ammobroma sonorae | Pholisma sonorae
Distribution The range of the species extends south into Mexico and west into the southwestern corner of California, and reportedly into Arizona. No recent plants have been located.
State Rank
State State Rank
Arizona S1
California S2
Habitat

Plants are found only in the loose shifting sand of the unstable dunes near Yuma, Arizona. Associated species include Tiquilia plicata, Eriogonum sp., and Ephedra sp. (Cothrun 1969, Felger 1980).

Ecological Relationships

Some of the host plant species include Tiquilia plicata, Psorothamnus emoryi, Ambrosia dumosa, and Pluchea sericea (Armstrong 1908a, 1980b). There has been speculation as to whether Pholisma absorbs water independently from host plants, but this has been discounted as Pholisma has no root hairs. Instead, water is probably absorbed through the many stomata on the scale-like leaves (Yatskievych 1985). This water taken directly from the sand can then move into the host plant during times of drought stress. Thus, the relationship between Pholisma and the host plant is not parasitic in the strictest sense.

Pollinators
Common Name Name in Text Association Type Source InteractionID
Butterflies & Moths
Butterflies Suspected Pollinator Floral Link
Small butterflies Not Specified Link
Beetles
beetles Suspected Pollinator Floral Link
Beetles Not Specified Link
Flies
Midges Leptoconops californiensis Confirmed Pollinator Link
Bee flies Aphoebantus marcidus Confirmed Pollinator Link
Flies Not Specified Link
Other
Sand wasps Bembix rugosa Confirmed Pollinator Link

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