CPC National Collection Plant Profile

Echinocereus viridiflorus var. davisii

Photographer:
Kathy Rice

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CPC National Collection Plant Profile

Echinocereus viridiflorus var. davisii


Family: 
Cactaceae  
Common Name: 
Davis' green pitaya
Author: 
(A.D. Houghton) Backeb.
Growth Habit: 
Shrub
CPC Number: 
1577

Distribution
Protection
Conservation
References


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Echinocereus viridiflorus var. davisiienlarge
Photographer: Kathy Rice


Echinocereus viridiflorus var. davisii is Not Sponsored
Primary custodian for this plant in the CPC National Collection of Endangered Plants is: 
Kathleen C. Rice contributed to this Plant Profile.

 
Echinocereus viridiflorus var. davisii


This diminutive cactus was first discovered in Texas by Arthur Houghton in 1931. Echinocereus viridiflorus var. davisii can grow up to 3 cm in diameter, with stems that are attractively marked with regularly spaced purplish horizontal stripes (Dorrel and Johnson 1970). Yellow-green flowers grow up through densely packed gray-colored spines. Greenish-purple fruits dehisce along a suture on the capsule's side, revealing up to 100 tiny black seeds (Leek and Miller 1982). During a drought (which most often occurs in late fall and early spring), plants utilize water stored in the stem for metabolic processes, causing a 'shrinking' effect and making plants difficult to find.

Distribution & Occurrence

State Range
  Texas
State Range of  Echinocereus viridiflorus var. davisii
Habitat
  The single known population occurs on a specific limestone substrate in west Texas, in a semi-desert grassland (Godfrey et al. 1973, USFWS 1984). A large percentage of the soil is covered by Selaginella sp., but other associated plants include Opuntia leptocaulis, Escobaria hesteri, Escobaria varicolor, Larrea tridentata and Dasyliron leiophyllum (USFWS 1984).

Distribution
  The majority of the limestone formation where this species occurs lies on privately owned land. Access to this site was historically allowed by the property owner. Since then, beginning approximately 25 years ago, the land has been inaccessible. Only a small portion of plants growing along a 20 m strip next to a road can now be reached. These plants are being monitored by the Texas Parks and Wildlife staff in cooperation with USFWS (1984). It is believed that the present range is the same as the historic range, as plants are very substrate-specific.

Number Left
  Numbers in remaining populations are unknown. All plants occur on one site located on a privately owned land. Reports indicate that several individuals exist, but these findings remain unverified.

Protection

Global Rank:  
G5T1
 
1/16/2002
Guide to Global Ranks
Federal Status:  
LE
 
10/24/1996
Guide to Federal Status
Recovery Plan:  
Yes
 
9/20/1984

State/Area Protection
  State/Area Rank Status Date  
  Texas S1 E 4/28/1987  

Conservation, Ecology & Research

Ecological Relationships
  It is suspected that the Selaginella substrate where these plants are found is a main factor for survival of Echinocereus viridiflorus var. davisii in its early life stages.

Threats
  Primary threats to this species include its restricted range and overcollecting (Weiniger 1979, USFWS 1984).

Current Research Summary
  Seeds are collected annually by Desert Botanical Garden as stipulated by the Texas Office of the USFWS. Germination is rapid and the percentages are high, but the survival rate of seedlings is low, even in cultivation, possibly due to the miniscule size of seedlings. Early germination techniques used were the Steve Brack screened boz method, where a wooden box covered with window screening houses pots of seeds, and is misted twice daily. This method ensures stability of the round seedlings in the soil, by reducing the size of water droplets reaching plantlets. (Desert Botanical Garden 2000)

Current Management Summary
  Management practices are not known for this species, but no cattle are observed grazing in the pasture where plants are located. Observations are made only for brief intervals twice annually.

Research Management Needs
  Because this species has such a limited range, understanding its habitat requirements and identifying new sites are essential. Studies related to the pollination biology and soil microbial associations should also be examined.

Ex Situ Needs
  Field collected seeds are needed from new plants in new locations in the pasture. The previously-collected seeds are stored both at Desert Botanical Garden and the National Seed Storage Lab in Ft. Collins, Colorado.
Serious consideration should be given to the prospect of legally offering F2 or later generations of offspring for sale to those who would otherwise collect in the wild.

References

Books (Single Authors)

Benson, L. 1982. The Cacti of the United States and Canada. Stanford, California: Stanford University Press. 1044p.

Correll, D.S.; Johnston, M.C. 1970. Manual of the vascular plants of Texas. Renner: Texas Research Foundation. 1881p.

Kartesz, J.T. 1993. Species distribution data for vascular plants of 70 geographical areas, from unpublished data files at the North Carolina Botanical Garden.

Kartesz, J.T. 1996. Species distribution data at state and province level for vascular plant taxa of the United States, Canada, and Greenland (accepted records), from unpublished data files at the North Carolina Botanical Garden.

Poole, J.M.; Riskind, D.H. 1987. Endangered, threatened, or protected native plants of Texas. Austin, TX: Texas Parks Wildlife Department.

Taylor, N.P. 1985. The genus Echinocereus. Portland, OR: Timber Press. 160p.

Weniger, D. 1984. Cacti of Texas and neighboring states: a field guide. Austin: University of Texas Press. 356p.

Books (Sections)

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Conference Proceedings

Poole, J.; Janssen, G.K. Managing and Monitoring Rare and Endangered Plants on Highway Rights-of-way in Texas. Gen. Tech. Rep. RM-GTR-283. Proceedings of the Southwestern Rare and Endangered Plant Conference; September 11-14; Flagstaff, AZ. In: Maschinski, J.; Hammond, H.D.; Holter, L., editors. 1996. USDA and US Forest Service. p 8-12.

Electronic Sources

(2000). Center for Plant Conservation's National Living Collection--Profiles. Desert Botanical Garden. http://www.dbg.org/Collections/cpc.html. Accessed: 2002.

(2002). Conserving Native Species in Brewster County. Texas Department of Agriculture. http://www.agr.state.tx.us/pesticide/endangered/pes_brewster1.htm. Accessed: 2002.

(2002). Texas Threatened and Endangered Plants--Profiles. Texas Parks and Wildlife. http://www.tpwd.state.tx.us/nature/endang/plants/index.htm. Accessed: 2002.

Journal Articles

Leuck, Edwin E.; Miller, John M. 1982. Pollination biology and chemotaxonomy of the Echinocereus viridiflorus complex (Cactaceae). American Journal of Botany. 69, 10: 1669-1672.

USFWS. 1976. Proposed Endangered Status for 1700 U.S. Plants. Federal Register. 41: 24523-24572.

USFWS. 1979. Determination that Echinocereus viridiflorus var. davisii and Coryphantha minima are Endangered Species. Federal Register. 44, 217: 64738-64740.

USFWS. 1979. Service Lists 32 Plants. Endangered Species Technical Bulletin. 4, 11: 1, 5-8.

USFWS. 1983. Regional Briefs-Region 2. Endangered Species Technical Bulletin. 8, 12: 2, 5.

USFWS. 1985. Plans for Cacti. Endangered Species Technical Bulletin. 10, 1: 7-9.

Reports

USFWS. 1984. Recovery plan for the Davis' green pitaya Echinocereus viridiflorus Engelm. var. davisii (Houghton) L. Benson. Albuquerque, N.M.: U.S. Fish & Wildlife Service. p.34.

Weniger, D. 1979. Status report on Echinocereus viridiflorus var. davisii. Albuquerque, New Mexico: U.S. Fish & Wildlife Service.

Theses

Leuck, Edwin E. 1980. Biosystematic studies in the Echinocereus viridiflorus complex. [Ph.D. Thesis]: University of Oklahoma. 122p.


  This profile was updated on 3/4/2010
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