" Portulacaria afra, the Elephant's Food or Spekboom:

a monograph which contains some of the areas of

both knowledge and ignorance pertaining to this plant "

© 1999-2014 by Robert J. Baran


 

TABLE OF CONTENTS
PART I
TAXONOMY
ORIGIN
HISTORICAL REFERENCES
APPEARANCE
THE TRUNK
THE BRANCHES
THE LEAVES
THE FLOWERS AND FRUIT
THE ROOTS
VARIETIES

PART II
TEMPERAMENT
PROPAGATION
HORTICULTURAL & OTHER USES
CONTAINERIZED
BIBLIOGRAPHY

PART III
  THE OTHER PORTULACARIA
THE FALSE PORTULACARIA
BIBLIOGRAPHY



PART IIb


BIBLIOGRAPHY


IMAGES

Bonsai Magazine, Bonsai Clubs International, September 1973, Vol. XII, No. 7, pg. 9 b&w photo  A small and medium jade grown from cuttings received 5 years earlier via airmail by Leon M. Pfeifer of New York.

Wu, Yee-Sun   Man Lung Artistic Pot Plants ; Hong Kong: Wing-lung Bank Ltd.; June 1974.  Enlarged second edition.  Color photo #242 on pg. 257 shows a 61 cm tall specimen with thin surface roots in a short brown hexagonal pot on a carved black lacquered stand.  The caption describes the plant as "Crassula obliqua (Crassulaceae)," but to this researcher the plant is really a P. afra.

Bonsai Magazine, BCI, December 1975, Vol. XIV, No. 10, Cover, color photo.  Article on pp. 301-302.  Given as 22" tall, informal upright potted in glazed dark blue container.  The tree had been in training for ten years after being in a nursery where its 8 gallon nursery can had rusted away and the plant was covering a 25 sq. ft. area.  Artist: James J. Smith.  Plant was shown in Miami, FL at the "New Bonsai Horizons" Exhibition in July 1975.

Bonsai Magazine, BCI, February 1976. Vol. XV, No. 1, Cover, b&w photo of same tree as Dec. 1975.  Caption on page 6.

Bonsai Magazine, BCI, January/February 1980. Vol. XIX, No. 1, pg. 21.  B&w photo of eight yr old, three in training with 18" spread, 24" high, 12/4" [sic] trunk diameter.  The tree is grown completely indoors.  Owned and photographed by Kenny Popp, President of Louisville BOnsai C.

Bonsai Magazine, BCI, April 1980. Vol. XIX, No. 3, pg. 103.  B&w photo of 23 in tall slant-style in an 11 inch brown glazed pot.  In training for one year, owned by Kenneth Popp.  B&w photo sent in by Lee Squires.

Bonsai Magazine, BCI, September 1980, Vol. XIX, No. 7, three b&w photos on pg. 226 with the folowing captions: "A Jade Plant cutting sent to Bob Burgess of Surrey, England in 1970 by Horace & Connie Hinds."  "A closer look at the trunk."  "The 'cutting' as it looked in 1978. Bob stated that there has [sic] been several hundred cuttings taken from this one and they are quite popular in his area."

Bonsai Magazine, BCI, May 1983, Vol. XXII, No. 4, Cover, b&w photo of 8" mame size in a small Japanese container.  The plant was in this pot for seven years.  Photo provided by Mrs. Nikunj S. Parekh, Bombay, India.  Caption on page 112.

Parekh, Jyoti and Nikunj Parekh   Wonderworld of Tropical Bonsai ; Bombay: Vakils, Feffer & Simons Ltd.; 1984, 1987.  Cover is a color photo of a cascade specimen.

Bonsai Magazine, BCI, July/Aug 1986. Vol. XXV, No. 4, pg. 16.  B&w photo from Houston Bonsai Society show.  Described as "elephant plant."

Clark, Randy   Outstanding American Bonsai ; Portland, OR: Timber Press; 1989.  Bonsai #48 (color photo by Peter Voynovich) on pg. 121 is an "Elephant Bush."  This wired 17" cascade was in training at the time for 4 of its 7 years by Ruth H. Delaney, MN.

World Tropical Bonsai Forum, Winter 1991.  Color cover.

Bonsai Magazine, BCI, May/June 1991. Vol. XXX No. 3, pg. 10.  Top right, small color photo captioned "Dwarf Jade Portulacaria afra by James J. Smith of Vero Beach, FL."  In the article "Succulents As Bonsai" by Jerry Kossler (pp. 9-10).

Bonsai Magazine, BCI, Sept/Oct 1993. Vol. XXXII, No. 5, pg. 32.  Bottom left, a small color photo of a specimen shown at WBFF '93.  Given as 24" high, 28" wide, informal upright, artist: James J. Smith, Florida.  This does not appear to be the same tree as on Dec. 1975 cover, but probably is the same as May/June 1991.

Bonsai Journal, American Bonsai Society, Winter 1994, Vol. 28, No. 4.  Cover, color.  Caption on page 131 reads "Elephant Bush, Portulacaria afra.   This tree was propagated from a large cutting taken around 1985, and grown in an oversized nursery container for about three years.  In 1988, the artist, Jim Smith, pruned it back drastically and styled it as a multi-trunk bonsai.  The rock on which it is planted is a native limestone rock colected from a road construction.  It is presently housed in the Pacific Rim Collection in Washington State."

Bonsai Journal, ABS, Fall 1999, Vol. 33, No. 3, pg. 115.  Bottom right, a quarter page color photo.  Caption reads "'Elephant's Food' ( Portulacaria afra ) trained in the double-trunk style by Doug and Gail Acker of the Phoenix Bonsai Society.  The tree measures 25" in height, is ten years old, and has been in training six years.  This tree was given the President's Award by Bonsai Clubs International, and was selected at the [ABS '99] symposium exhibition by BCI past president Mary Bloomer and Chase Rosade, in Solita Rosade's absence.  (Photo by Hector Espinosa)"

Portulacaria afra by Doug and Gail Acker, photo by Hector Espinosa


Nichin Bonsai, 3/2003.  Color cover.  Caption at bottom of inside front cover: "Bonsai of Portulacaria Afra Jade Tree : Age 8 years training  Ht : 35 cmc.  Bonsai by Archana & Krishna Gupta"

Douthitt, Jack   Bonsai -- The Art of Living Sculpture (NY: Rizzoli International Publications, Inc.; 2001), pg. 105, color photo of root in rock specimen from Pacific Rim Bonsai Collection.

Coussins, Craig   Bonsai Master Class (Devon, England: D&S Books Ltd.; 2006), pg. 105, color photo of forest on cover, plus seven other small color pics in Jim Smith's section on "Species for warmer climates or inddor cultivation," pp. 194-196.

Grünwald, Ofer   "'Altneuland' The story of bonsai in Israel, a kind of small revolution," Bonsai Focus, 147/124, 5/2013 Sept/Oct, pg. 19, color photo of twin-trunk P. afra next to Moshe Emergui.


TEXT with or without IMAGES

                  Additional biographical details for Jacquin from http://www.nhm-wien.ac.at/nhm/Mineral/Jacquine.htm.

                  Additional material courtesy of Prof. Gideon F. Smith, Director of Research, and his staff at the National Botanical Institute, Petoria, South Africa.

                  Alluaudia procera listing, Horticopia ® On-line Plant Information, http://www.horticopia.com/hortpix/html/pc425.htm

                  Animal Feed Resources Information System, http://www.fao.org/ag/AGA/AGAP/FRG/afris/Data/430.HTM

                  Bonsai Clubs International Species Guide, Portulacaria, http://www.bonsai-bci.com/species/portulacaria.html

                  Budding cut brought to RJB's attention by Paul Steele.

                  Caryophyllales, http://www.mobot.org/mobot/research/apweb/orders/Caryophyllalesweb.htm

                  Elephant diet details per Graaff-Reinet web site, http://www.graaffreinet.co.za/plant3.html

                  Information and questions as to fossil and early forms sparked by reply to e-mail from Mike Pippenger at Truman State Univerity in Missouri, Oct 9, 2000, asking about such things.

                  Names in current use for extant plant genera, entry for Portulacaria  Jacq., http://www.bgbm.fu-berlin.de/scripts/asp/IAPT/ncugentry.asp?name=Portulacaria

                  Portulacaria afra Jacq.,  National Botanical Institute, South Africa, http://www.plantzafrica.com/plantnop/portulacarafra.htm , accessed 04/16/04

                  Royal Botanic Gardens, Kew, SEPASAL  project, http://www.rbgkew.org.uk/servlets/sepaweb

                  Taxa described by Jacq., Agriculture and Agri-Food Canada web site, Integrated Taxonomic Information System, http://sis.agr.gc.ca/pls/itisca .  Accessed on 11/02/01, with a hard copy printed.  Several attempts during 2003 to relocate this section using the site's search engine have failed. 

                  Britannica Atlas ; Chicago et al: Encyclopedia Britannica, Inc.; 1982.  Pp. 158-159, 220. 

                  The Marshall Cavendish Illustrated Encyclopedia of Plants and Earth Sciences ; Bellmore, NY: Marshall Cavendish Corporation; 1988. Reference Edition Published 1990.  Vol. 1, pp. 32-33, Vol. 4, pp. 424-425.

                  The Natural Gardening Association Dictionary of Horticulture ; New York: Viking; 1994.  Produced by The Philip Lief Group, Inc.  Published by the Penguin Group.  Pp. 430-431.

                  The New York Botanical Garden Illustrated Encyclopedia of Horticulture ; NY: Garland Publishing, Inc.; 1981. Vol. 8, pp. 266-267.  After the genus name states "One of the two species...is commonly cultivated."  but only lists one species, afra

                  Oxford English Dictionary, Second Edition ; Oxford: Clarendon Press; 1989.  Vol. XVI, pg. 186.

                  "Shamwari -- bringing back the past,"  Getaway Magazine, February 1994, http://www.getawaytoafrica.com/content/magazine/features/feature.asp?id=549&fe_page=1

                  Smithsonian Natural History ; New York: Dorling Kindersley Limited; 2010 First American Edition.  Pp. 122, 124, 128, 165.

                  Some varieties can be seen at http://www.rareplants.com/succ-pr.html.

                  Sunset Western Gardening Guide, pg. 544 of 2001 edition, pp. 425, 512 of 1979 edition, and pg. 380 of 1967 edition.  Small black and green illustration of borderline identification value.

                  Taylor's Encyclopedia of Gardening ; Boston: Houghton Mifflin Company; 1961. Fourth Edition. Pp. 88, 859, 964-965, 1296. 

Applequist, Wendy L. and Robert S. Wallace  "Expanded circumscription of Didieraceae and its division into three subfamilies," Adansonia, sér. 3, 2003, 25(1): 13-16.  http://cimbad.mnhn.fr/publication/adanson/a03n1a2.pdf

Bailey, L.H. Manual of Cultivated Plants ; NY: MacMillan Publishing Company; 1949.  Revised edition.  Pp. 364-365.  After the genus name states "Two [sic] S. African fleshy shrubs or small trees...", but only lists one species, afra.

Branford, Jean  A Dictionary of South African English ; Cape Town: Oxford University Press; 1980.  New Enlarged Edition.  Pg. 273.

Bredenkamp, G., Granger, J.E. & van Rooyen, N. 1996. Moist Sandy Highveld Grassland. In: Low, A.B. & Robelo, A.G. (eds) Vegetation of South Africa, Lesotho and Swaziland. Department of Environmental Affairs and Tourism, Pretoria.  Per http://www.ngo.grida.no/soesa/nsoer/Data/vegrsa/veg8.htm .

Brickell, Christopher (Ed.-in-chief)  The American Horticultural Society Encyclopedia of Garden Plants; New York: Macmillan Publishing Company; 1989, 1992.  Small color photo upper left pg. 121.  Text pg. 542.

Brookes, John and Kenneth A. Beckett & Thomas H. Everett The Gardener's Index of Plants & Flowers ; New York: Collier Books, Macmillan Publishing Company; 1987.  Pp. 102-103.

Brown, J.R.  "The flowering of Portulacaria afra Jacq.," Cactus & Succulent Journal, Vol. XIX, 1947, pp. 140-141.

Bryant, Charles and Brita Lomba  African trees:a photographic exploration; Juta and Company Ltd, 2004.  Pg. 26.

Burtt-Davy, J.  A manual of the flowering plants and ferns of the Transvaal, with Swaziland, South Africa ; London; 1926.

Chidamian, Claude  The Book of Cacti and Other Succulents ; New York: The American Garden Guild and Doubleday & Company, Inc.; 1958.  Pg. 131.

Court, Doreen   Succulent flora of Southern Africa ; Rotterdam: A.A. Balkema; 1981.  Pg. 109, which states the genus has two species, and gives the second as " P. pygmaea ( Ceraria pygmaea )."  Also is the source of the flowering in Vienna note.  Per pg. 50 of the CRC Press, 2000 Revised Edition of Court's book, the C.A Smith reference to the sour and sweet forms. That reference is apparently SMITH C.A. , 1966, Common Names of South African Plants, Botanical Survey Memoir No 35.

Coussins, Craig   Bonsai Master Class ; Devon, England: D&S Books Ltd.; 2006.  Cover color photograph of a Portulacaria forest, also shown on pg. 254, with other information by Jim Smith and eight smaller color photos on pp. 194-196. 

Cuénoud, Philippe, et al   "Molecular phylogenetics of Caryophyllales based on nuclear 18S rDNA and plastid rbcL, atpB, and matK DNA sequences," American Journal of Botany ; 2002; 89:132-144.   Per http://www.amjbot.org/cgi/content/full/89/1/132#F303

Dyer, R.A.  " Portulacaria afra," The Flowering Plants of Africa ; 1978. 45: t. 1763.

Exell, A.W. and H. Wild (ed.)   Flora Zambesiaca ; London: Published on behalf of the Governments of Portugal, The Federation of Rhodesia and Nyasaland, and the United Kingdom by the Crown Agents for Oversea Governments and Administrations; 1960.  Pg. 363.

Gillispie, Charles Coulston (editor-in-chief)  Dictionary of Scientific Biography ; NY: Charles Scribner's Sons; 1980. Vol. 7, pp. 57-59.  None of the book titles listed for Jacquin contain any obvious references to Africa.

Glavich, Tom   "Succulents of the Month September 2002: Didieraceae, Alluaudia," Los Angeles Cactus and Succulent Society.

Glimin-Lacy, Janice and Peter B. Kaufman  Botany Illustrated, Introduction to Plants, Major Groups, Flowering Plant Families ; NY: Van Nostrand Reinhold; 1984, pp. 4, 75.

Graf, Alfred Byrd  Exotica 3: Pictorial Cyclopedia of Exotic Plants ; Rutherford, NJ: Roehrs Company; 1957, 1959, 1963. B&w photos of varieties "aurea" (in Carlsbad, CA), "variegata", and unnamed on pg. 1395. B&w photo of unnamed green variety in the Transvaal, pg. 1396. B&w drawing of inflorescense on pg. 1471.  Text on pg. 1697.

Griffiths, Mark  Index of Garden Plants ; Portland, OR: Timber Press; 1992, 1994.  Pg. 925.  Derived from The New Royal Horticultural Society Dictionary.

Hankey, Andrew and Walter Sisulu NBG  "Portulacaria afra Jacq.," http://www.plantzafrica.com/plantnop/portulacarafra.htm.

Holttum, R.E. and Ivan Enoch   Gardening in the Tropics ; Portland, OR: Timber Press, Inc.  ©1991 Times Editions Ptc Ltd.  Reprinted 1995, 1997, 1999.  Per pp. 240-241: "In the last few years, this plant has appeared in Malaysia...  Flowers are sometimes produced and these are small with pink petals."

Jacobsen, Hermann  A Handbook of Succulent Plants ; Poole Dorset: Blandford Press; 1954.  English language edition 1960.  Vol. Two, pg. 745.

Jacobson, Arthur Lee  "Plant of the Month: December 2008," http://www.arthurleej.com/p-o-m-Dec08.html.

Killick, D.J.B. (ed.)   The Flowering Plants of Africa, Botanical Research Institute, Dept. of Agricultural Technical Services, 45:1763.  With illustration of flowering branch and four close-ups of flower.

Lamb, Edgar and Brian M.   The Illustrated Reference on Cacti & Other Succulents ; Poole Dorest: Blandford Press; 1971-1977.  Second Edition 1971, Reprinted 1977.  Vol. 3, pg. 830 w/b&w photo.

Lesniewicz, Paul   Bonsai in Your Home ; NY: Sterling Publishing Co., Inc.; 1994.  Color photo of root-over-rock style on title page, color of slant style on p. 154, and color of outer branch on p. 155 with care instruction text for " Portulacaria afra Elephant bush."

Long, Chris (compiler)   "PORTULACACEAE" in "Swaziland's Flora - siSwati Names and Uses"

Lord, Ernest E.   Shrubs And Trees for Australian Gardens ; Melbourne & Sydney: Lothian Publishing Co. Pty. Ltd.; 1970.  Fourth Edition.  Completely Revised 1964, Reprinted 1974 (Partial Revision 1970).  Pg. 301.

Lust, John  The Herb Book ; NY; Bantam Books; © 1974, Benedict Lust Publications.   Pp. 501, 503, 505.

Martin, Margaret J. and Peter R. Chapman   Succulents and their cultivation ; New York: Charles Scribner's Sons; 1977.  First published in U.S.A. in 1978.  Pg. 261 which states "The genus Portulacaria is monotypic, containing only P. afra...  The minute flowers are pale green." [sic]

McGourtey, Frederick (editor)  Handbook on Bonsai for Indoors ; Brooklyn, NY: Brooklyn Botanic Garden. Fourteenth printing, Jan. 1985. Pp. 49, 63.

Medley Wood, J. and Maurice S. Evans   Natal Plants ; Durban: under the Auspices of the Natal Government and Durban Botanic Society; 1899.  Vol. 1.  Pp. 63-64.  With five detailed line drawings of the flowers as Plate 78, "Drawn and described from specimens in flower on Berea, October, 1898."

Miller, Mary J.  "Portulacaria afra, a succulent in tree form," Bonsai Today, No. 68, 2000-4, July-August 2000, pp. 39-44.  With seven color photographs by Jim Smith.  A very good article.  This also is the first published reference to this web site monograph (which was discovered after most of the article was written).  Note:  much of the information in the article that pertains to use as bonsai and which is also on this site originated in the article.

Moran, Reid  "Spekboom Blooms," Cactus & Succulent Journal, Vol. XLV, No. 1.  January-February 1973.  Pp. 71-73.  With three wonderful close-up photos of the flowers.

Oakes, A.J.  "Portulacaria afra Jacq. - a potential browse plant," Economic Botany, No. 27, pp. 413-416.

Palmer, Eve and Norah Pitman   Trees of Southern Africa ; Cape Town: A.A. Balkema; 1972.  Volume One.  (First edition published in 1961)  Pp. 85, 113, 121, 290, 567-569.  B&w photos on pp. 124, 254 (thatched hut), and 566 (a large specimen in full and a close-up of its trunk).

Perry, Bob   Landscape Plants for Western Regions ; Claremont, CA: Land Design Publishing; 1992.  Pg. 251.  Color Plates 823 and 824, the latter showing many flower clusters.

Pilbeam, John   The Instant Guide to Healthy Succulents ; NY: Times Books, a division of Random House, Inc.; ©1984 Eurobook Limited.  First American Edition.  Originally published in Great Britain in 1984 as How to Care For Your Succulents by Peter Lowe, London.  Pp. 70-71, with 4 color photos and drawings and two small b&w line drawings.  The first page states that the flowers "are similar to groundsel, yellow and daisy-like."

Pitkin, Brian R. "Family NERIIDAE," Australasian/Oceanian Diptera Catalog -- Web Version, http://hbs.bishopmuseum.org/aocat/nerridae.html

Rauh, Werner   The Wonderful World of Succulents ; Washington, D.C.: Smithsonian Institution Press; 1984.  Translated by Harvey L. Kendall.  Pp. 133-134.

Rojas, Christine E.   "Portulacaria afra, The Sensuous Succulent," World Tropical Bonsai Forum, Winter 1991, pp. 9-14.  Photography by Carlos O. Rojas and James J. Smith, illustrations by Patrick Giacobbe.

Santiago, Steve   "Vero Beach botanist donates 100 bonsai to Heathcote for new exhibit," TCPalm, January 5, 2011, photo by Eric Hasert.

Schmidt, Ernst and Mervyn Lötter, Warren McCleland   Trees and shrubs of Mpumalanga and Kruger National Park ; Johannesburg: Jacana; 2002.  Pg. 106.

Schoech, Wayne   "A True Gentleman & A Very Large Tree," Bonsai Bark blog, 05/21/2012, with correction of "300 year old" specimen age in 05/21/12 post by Patrick Giacobbe, Bonsai curator for the James J. Smith Bonsai Gallery.

Shearing, David   Karoo, South African Wild Flower Guide 6 ; Kirstenbosch, Claremont: Botanical Society of South Africa in association with National Botanical Institute; 1994.  Pp. 68-69.  Includes illustration of flowering branch by Katryn Van Heerden.  Source of sweet eastern-northern and sour southerly-westerly aspects.

Sim, Thomas R.   The Forests and Forest Flora of The Colony of the Cape of Good Hope ; Aberdeen, Scotland: under the Authority of the Government of the Cape of Good Hope; 1907.  Pp. 133-134.  With seven line drawings as Section II on Plate XIX.

Sonder, Otto Wilhelm   Flora Capensis ; London: Lovell Reeve & Co.; 1862.  Vol. 2.  Pp. 385-386.

Trager, James   The People's Chronology ; New York: Henry Holt and Company; 1992, 1994.  Pp. 244, 340, 390.

USDA, ARS, National Genetic Resources Program.   Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland.  Available: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?29459 (29 May 2001).

Van Wyk, Ben-Erik and Nigel Gericke   People's Plants ; Pretoria: Briza Publications; 2000.  Pg. 74.

Watt, John Mitchell and Maria Gerdina Breyer-Brandwijk   The Medicinal and Poisonous Plants of Southern and Eastern Africa ; Edinburgh: E. & S. Livingstone Ltd; 1962.  Pg. 869.





This
WRA Species Report - Hawaiian Ecosystems at Risk project, with a nice summary of a wide range of info about this plant (with a few citations to THIS article).



Also, a recipe for kudu, spekboom-fed or otherwise, was pointed out to RJB by Jeff Cammack in a personal e-mail 24 Mar 2009.  



References Not Yet Checked include the following:


Applequist, W. L., Wallace, R. S.  1998. "Portulacaria afra ribosomal protein L16 (rpl16) gene, chloroplast gene encoding chloroplast protein, partial cds"  Direct Submission (22-OCT-1998) Botany Department, Iowa State University, 353 Bessey Hall, Ames, IA 50011, USA.

Applequist, W. L., Wallace, R. S.  2001. "Phylogeny of the portulacaceous cohort based on ndhF sequence data."  Syst. Bot. 26 (2), 406-419.

Aucamp, A.J., L.G. Howe, D.W.W.Q. Smith and J.O. Grunow.  1980.  "Die invloed van ontblaring op Portulacaria afra." Proceedings of the Grassland Soc. of Southern Africa, 15:179-184.    (In Afrikaans, with English summary.) 

Huerta, Alfredo José  1987.  Induction of Crassulacean acid metabolism in Portulacaria afra (L.) Jacq. (Portulacaceae) (Riverside: Publisher University of California, Riverside)

Ras, A.M.  1990.  "Die invloed van ontblaring en vog op die tanienen polifenolinhoud van Portulacaria afra". J. of the Grassland Soc. of Southern Africa, 7:139-143.    (In Afrikaans, with English summary.) 
[Both citations per References section in Sustainability Indicators for Natural Resource Management & Policy, Working Paper 4, Natural Resource Management and Policy in Eastern Cape Province, South Africa: Overview Paper, edited by P.C. Lent, P.F. Scogings and W. Van Averbeke (Alice, South Africa: Agricultural and Rural Development Research Institute, University of Fort Hare, February 2000).] 
 

Guralnick, L.J., P.A. Rorabaugh, and Z. Hanscom, III. 1984. "Influence of photoperiod and leaf age on Crassulacean Acid Metabolism in Portulacaria afra (L.) Jacq."  Plant Physiol. 75:454-457.

Guralnick, L.J., P.A. Rorabaugh, and Z. Hanscom, III. 1984. "Seasonal shifts of photosynthesis in Portulacaria afra (L.) Jacq."  Plant Physiol. 76:643-646. 
[Both citations per SDSU Faculty Profile for Hanscom, Zac, III  http://www.bio.sdsu.edu/faculty/hanscom.html]

Guralnick, L.J. and I.P. Ting.  1986.  "Seasonal drought and rewatering responses in Portulacaria afra (L.) Jacq." Oecologia 70:85-91.

Guralnick, L.J. and I.P. Ting.  1987.  "Physiological changes in Portulacaria afra (L.) Jacq. during a summer drought and rewatering"  Plant Physiol. 85:481-486.

Guralnick, L.J. and I.P. Ting.  1988.  "Seasonal Patterns of water relations and enzyme activity of the facultative CAM plant Portulacaria afra (L.) Jacq."  Plant, Cell & Environment 11:811-818.

Guralnick, L.J., G. Goldstein, R.L. Heath, and I.P. Ting.  1992.  "Fluorescence quenching in the varied photosynthetic modes of Portulacaria afra (L.) Jacq."  Plant Physiol. 99:1309-1313.
[Four citations per Research Publications for G.L. Guralnick http://www.wou.edu/las/natsci_math/biology/gural/publications.htm]
 
Behnke HD, Mabry TJ, Eifert IJ, Pop L. P-Type Sieve-Element Plastids and Betalains in Portulacaceae (Including Ceraria, Portulacaria, Talinella). Canadian Journal of Botany-Revue Canadienne De Botanique 1975; 53(19): 2103-2109.
[Citation per
"Betalains related papers: sorted by year of publication (last check 3rd August 2003)," http://www2.unil.ch/lpc/docs/bvbibl.htm  


Huerta, A. J. and I.P. Ting.  1988. "Effects of various levels of CO2 on the induction of crassulacean acid metabolism in Portulacaria afra."  Plant Physiol. 88(1):183-188.

[Citation per MU faculty profile for Alfredo J. Huerta, http://www.cas.muohio.edu/botany/bot/ah.html ]
 

Lee, D.M. and S.M. Assmann.  1992.  "Stomatal responses to light in the facultative crassulacean acid metabolism species, Portulacaria afra," Physiologia Plantarum   85:35-42.
[Citation per PSU faculty profile for Sarah M. Assmann, http://www.bio.psu.edu/People/Faculty/Assmann/]
 

Ting, I.P.  1981.  "Effects of abscisic acid on CAM in Portulacaria afra," Photosynth Res. 2: 39-48.

Ting, I.P. and Z. Hanscom, III,  "Induction of Acid Metabolism in Portulacaria afra," Plant Physiol. 1977 Mar; 59(3): 511-514.

Zacharias, P J K  and G C Stuart-Hill, Proceedings of the First Valley Bushveld/Subtropical Thicket Symposium   (J Midgley;  Special Publication 1991), whose Part IV, Spekboom MiniSymposium, contains the following tantalizing topics:
"Adaption of Portulacaria afra to defoliation" by G C Stuart-Hill; 
"Aspects of the germination of Portulacaria afra (L.) Jacq." by  B H Whiting; 
"The influence of defoliation, irrigation and climate on the condensed tannin and total polyphenol content of Portulacaria afra " by A M Ras <same as above?>; 
"Spekboom dynamics" by  G P von Maltitz;
"How does spekboom survive drought?" by C W Stoltz;
"On the demise of spekboom in Natal's Valley Bushveld" by C R Hurt 
[Citation per http://www.ru.ac.za/institutes/rgi/gssa/specpu2.htm ]


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Part 3



This ongoing monograph was begun in the summer of 1993,
at a time when Portulacaria afra was seemingly the only bonsai that would survive for me in the Phoenix area,
and was then first put on this web site in early July of 1999.
This work was last updated 22 February 2014.
If you have comments or thoughts concerning this, please e-mail me, rjb@phoenixbonsai.com


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