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Dr Colin Walker

Profile summary

  • Visiting Informal Academic
  • Honorary Associate
  • Faculty of Science, Technology, Engineering & Mathematics
  • School of Environment, Earth & Ecosystem Sciences
  • colin.walker

Professional biography

  • I am currently an Honorary Associate. My research interests are in biosystematics, biodiversity and conservation of succulent plants.
  • My passion in life is succulent plants that started as a school boy in 1967, when I grew a few plants on windowsills at my parent's house. Even at this early stage my interests were with the other succulents, mainly Adromischus, Aloe, Gasteria, and Haworthia. I now has a modest-sized greenhouse collection of succulents, with most of the major families of succulents represented; many tender plants, along with a collection of sansevierias, also occupy many windowsills in the house.
  • Over the years I have played various roles in the “succulent scene”. My involvement with the International Asclepiad Society started in 1977, since when I have been Treasurer, Membership Secretary, Chairman and Editor of the journal Asklepios. Editor of Bradleya, scientific Yearbook of the British Cactus & Succulent Society, 2001-2012. Currently chairman, British Cactus & Succulent Society (2013 to date). Recently became chairman of the British Cactus & Succulent Society's Research Committee.
  • A member of the International Organisation for Succulent Plant Research (IOS) and Fellow of The Linnean Society.
  • I have published many articles and papers in various succulent journals around the world. Contributed to the Illustrated Handbook of Succulent Plants (2001–2003) on families such as the Crassulaceae, Bombacaceae, Dracaenaceae, Nolinaceae, and Urticaceae, and I'm currently working on the revised second edition. 
  • In 2011 I co-authored Aloes - The Definitive Guide, co-published by The Royal Botanic Gardens Kew and The British Cactus & Succulent Society. This is a major volume dealing with a large genus of succulents, some of which, notably Aloe vera, are of major economic importance.
  • As well as growing and writing about succulents, my other passion is collecting literature on these plants, and I now has an extensive library of books, booklets, and periodicals, ranging from very technical monographs through to novels, children’s books and even comic books.
  • I’m married to Marjorie and we have a daughter, Amy.

                                                                                                                                       

 

Research interests

Present research interests are centred around the biosystematics, biodiversity and conservation of succulent plants, notably members of the genera Aloe and Agave. Current topics:

​(1) Writing revised entries for the second edition of the Illustrated Handbook of Succulent Plants, a multi-volume, multi-author work to be published both online and in hardcopy by Springer, Berlin. My mains contributions are as follows:

Asparagaceae: Beaucarnea, Dasylirion, Dracaena, Nolina.

Laxmanniaceae: Cordyline.

Malvaceae: Adansonia, Cavanillesia, Ceiba, Pseudobombax.

Crassulaceae: Umbilicus.

Urticaceae: Laportea, Obetia, Pilea, Sarcopilea.

Asteraceae: Baeriopsis.

(2) The genus Aloe in Ethiopia and Eritrea. 

(3) Biodiversity of the genus Agave in Mexico and the Caribbean.

I have been an invited speaker at several international conferences including: the Cactus & Succulent Society of America, San Francisco (1995); the Cactus & Succulent Society of New Zealand, New Plymouth (2000); The Succulent Plants of Eastern Africa, Verbania, Italy (2002), the Cactus & Succulent Society of New Zealand, Auckland (2005), the Cactus & Succulent Society of New South Wales, Australia (2010), the Cactus & Succulent Society of America, Mid-western Conference, Boston (2010), the Cactus & Succulent Society of America, Austin, Texas (2011), the Haworthia Society (2019). 

Currently chairman of the British Cactus & Succulent Society's Research Committee, which awards research grants to support projects that provide new information on the biology, propagation or cultivation of succulent plants.        

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Publications

Echeveria agavoides and some of its cultivars (2024-06-01)
Walker, Colin C.
Cactus and succulent review(41) (pp. 17-21)

Aloe castilloniae J.-B. Castillon - a highly localised dwarf Madagascan endemic (2024-06)
Walker, Colin C.
Haworthiad, 38(2) (pp. 48-51)

Succulents contained: Huernia thuretii (2024-06)
Walker, Colin
CactusWorld, 42(2) (pp. 150-150)

Aloidendron pillansii (L.Guthrie) Klopper & Gideon F.Sm. - a review of a Critically Endangered southern African tree aloe (2024-06)
Walker, Colin
CactusWorld, 42(2) (pp. 89-99)

Contrasting cotyledons (2024-03)
Walker, Colin
Cactus & Succulent Review(40) (pp. 25-33)

[Book review]. Margulies, Jared D. The Cactus Hunters. Desire and Extinction in the Illicit Succulent Trade (2024-03)
Walker, Colin C.
CactusWorld, 42(1) (pp. 78-79)

[Book review] Antonelli, A. et al. State of the World's Plants and Fungi 2023 (2024-03)
Walker, Colin C.
CactusWorld, 42(1) (pp. 79-80)

Succulents contained. Didierea madagascariensis (2024-03)
Walker, Colin C.
CactusWorld, 42(1) (pp. 30-30)

Pachyphytum news (2024-03)
Walker, Colin C.
CactusWorld, 42(1) (pp. 72-74)

Aloe secundiflora Engler - a widespread tropical East African species (2024-02-22)
Walker, Colin
Haworthiad, 38(1) (pp. 8-13)

Two first flowering events: Ceropegia dichotoma and Orbea hardyi (2024-02)
Walker, Colin
New Zealand Cactus & Succulent Journal, 77(1) (pp. 16-19)

William Taylor Marshall: His Contributions to Succulent Plant Study and a Full Bibliography of His Published Work (2023-12)
Walker, Colin C. and Schultz, David M.
Haseltonia, 30(1) (pp. 27-48)

[Book Review] New Literature. Flowering Plants of Africa, Volume 68, June, 2023 (2023-12)
Walker, Colin
CactusWorld, 41(4) (pp. 339-339)

Succulents contained. Gasteria bicolor var. lilliputana (2023-12)
Walker, Colin
CactusWorld, 41(4) (pp. 310-310)

Aloe pendens Forsskal - a cliff-dwelling species from the Yemen (2023-10)
Walker, Colin
Haworthiad, 37(3) (pp. 72-75)

Ceropegia armandii : a remarkable dimorphic Madagascan endemic (2023-09-01)
Walker, Colin
Cactus & Succulent Review(38) (pp. 15-18)

Aloe whitcombei Lavranos - a unique and highly localised Omani endemic (2023-06)
Walker, Colin
Haworthiad, 37(2) (pp. 46-48)

Mangaves (2023-06)
Walker, Colin
Cactus & Succulent Review(37) (pp. 5-10)

Succulents contained: Euphorbia confinalis subsp. confinalis (2023-06)
Walker, Colin
CactusWorld, 41(2) (pp. 154-154)

Stapelia hirsuta (2023-03)
Walker, Colin
Cactus & Succulent Review(36) (pp. 15-17)

Agave nizandensis - a unique dwarf Mexican species (2023-03)
Walker, Colin
CactusWorld, 41(1) (pp. 51-55)

Succulents contained: Haemanthus albiflos (2023-03)
Walker, Colin
CactusWorld, 41(1) (pp. 34-34)

Tropical East African aloes: conservation status, uses and threats (2023-03)
Walker, Colin
CactusWorld, 41(1) (pp. 75-76)

New literature. Cristini, Marco. The genus Aeonium (2023-03)
Walker, Colin
CactusWorld, 41(1) (pp. 81-82)

Aloe fibrosa - a shrubby East African species (2023-02)
Walker, Colin
Haworthiad, 37(1) (pp. 14-16)

Sansevierias: an introduction (2023-01)
Walker, Colin
Cactus and Succulent Journal of NSW, 33(3 & 4) (pp. 33-43)

Two contrasting stapelias (2023)
Walker, Colin
New Zealand Cactus & Succulent Journal, 76(1) (pp. 23-26)

Orbea hardyi: A creeping stapeliad endemic to northern South Africa (2023)
Walker, Colin
Cactus and Succulent review(39) (pp. 4-6)

Euphorbia evolution and taxonomy (2022-12)
Walker, Colin
CactusWorld, 40(4) (pp. 299-300)

Madagascan euphorbias (2022-12)
Walker, Colin
CactusWorld, 40(4) (pp. 300-301)

Euphorbia susannae is endangered in the wild (2022-12)
Walker, Colin
CactusWorld, 40(4) (pp. 301-301)

The history and flowering of Agave xleopoldii (2022-12)
Walker, Colin
Cactus & Succulent Review(35) (pp. 9-12)

Succulents contained: Sansevieria subspicata (2022-12)
Walker, Colin
CactusWorld, 40(4) (pp. 262-262)

An introduction to Mexican Sedums (2022-11)
Walker, Colin
New Zealand Cactus & Succulent Journal, 75(2) (pp. 28-34)

Aloe jucunda - a highly localised, critically endangered Somalian endemic (2022-10)
Walker, Colin
Haworthiad, 36(2) (pp. 61-63)

Rhipsalis pilocarpa. A rare and localised Brazilian endemic (2022-09)
Walker, Colin
Cactus and Succulent Review, 34 (pp. 8-10)

Stapelia leenderztiae - a uniquely large, tubular-flowered species (2022-09)
Walker, Colin
CactusWorld, 40(3) (pp. 216-218)

Aloe palmiformis - an Angolan endemic (2022-09)
Walker, Colin
CactusWorld, 40(3) (pp. 175-178)

Chichimecactus: a new genus (2022-09)
Walker, Colin
CactusWorld, 40(3) (pp. 227-227)

Succulents contained: Monanthes polyphylla subsp. polyphylla (2022-09)
Walker, Colin
CactusWorld, 40(3) (pp. 212-212)

Echeveria cuspidata (2022-06)
Walker, Colin
Cactus & Succulent Review(33) (pp. 10-12)

Desmidorchis survives as a conserved name (2022-06)
Walker, Colin
CactusWorld, 40(2) (pp. 147-148)

Two recently described spotted-leaved, endemic Kenyan Aloes (2022-06)
Walker, Colin
Haworthiad, 36(2) (pp. 31-33)

Succulents contained: Eulychnia acida (2022-06)
Walker, Colin
CactusWorld, 40(2) (pp. 104-104)

Palmer's Culture des Cactées - a rare cactus book (2022-05)
Walker, Colin
Bradleya, 40 (pp. 231-248)

Succulents contained: Agave montana (2022-03-17)
Walker, Colin
CactusWorld, 40(1) (pp. 71-71)

Cotyledon - a small, highly diverse and complex African genus (2022-03)
Walker, Colin
CactusWorld, 40(1) (pp. 6-15)

A couple of cotyledons (2022-02)
Walker, Colin
New Zealand Cactus & Succulent Journal, 75(1) (pp. 10-14)

Agave × leopoldii (2022)
Walker, Colin
Cactus and Succulent Journal of NSW, 33(5 & 6) (pp. 78-82)

Palmer's Culture des Cactées – a rare cactus book (2022)
Walker, Colin C.
Bradleya, 2022(40) (pp. 231-248)

Sansevieria pinguicula - the 'walking' Sansevieria (2021-12)
Walker, Colin
Cactus & Succulent Review(31) (pp. 17-20)

Succulents contained: Sedum lucidum (2021-12)
Walker, Colin
CactusWorld, 39(4) (pp. 300-300)

Aristaloe aristata: a unique, monotypic species (2021-10)
Walker, Colin
Haworthiad, 35(3) (pp. 76-79)

Aloe jacksonii updated (2021-10)
Walker, Colin
Haworthiad, 35 (p 59)

Three South African Crassulas and the botanical art of Baron von Jacquin (2021-09)
Walker, Colin
Cactus & Succulent Review, 30 (pp. 31-39)

Stapelia divaricata Masson - the rarest and most localised species of Stapelia (2021-09)
Walker, Colin
CactusWorld, 39(3) (pp. 247-249)

Atlantic Aeoniums (2021-08)
Walker, Colin
New Zealand Cactus & Succulent Journal, 74(2) (pp. 20-34)

Kalanchoe tomentosa (2021-06)
Walker, Colin
Cactus and Succulent Review(29) (p 38)

State of the world's plants and fungi (2021-06)
Walker, Colin
CactusWorld, 39(2) (pp. 161-162)

Dragon trees updated (2021-06)
Walker, Colin
CactusWorld, 39(2) (pp. 165-165)

A survey of succulents of the mallow family (Malvaceae) (2021-06)
Walker, Colin
CactusWorld, 39(2) (pp. 135-148)

Heidi Hartmann and a life with mesembs (2021-06)
Walker, Colin
CactusWorld, 39 (pp. 164-165)

Aloe squarrosa Baker - a unique and highly localised Socotran endemic (2021-06)
Walker, Colin
Haworthiad, 35(2) (pp. 50-53)

Aloiampelos ciliaris var. ciliaris. Asphodelaceae: Alooideae (2021-06)
Smith, G. F.; Figueiredo, E.; Klopper, R. R.; Crouch, N. R.; Walker, C. C. and Condy, Gillian
Flowering Plants of Africa, 67 (pp. 18-30)

Kalanchoe beharensis. Crassulaceae: Kalanchooideae (2021-06)
Smith, G. F.; Figueiredo, E.; Walker, C. C. and Condy, Gillian
Flowering Plants of Africa, 67 (pp. 50-59)

The succulents of Portmeirion Pottery (2021-03)
Walker, Colin
Cactus & Succulent Review(28) (pp. 47-53)

Agave evolution and taxonomy (2021-03)
Walker, Colin
CactusWorld, 39(1) (pp. 73-74)

A review of the Euphorbia schinzii complex in Southern Africa (2021-03)
Walker, Colin
CactusWorld, 39(1) (pp. 74-75)

Halting plant extinction webinar (November 2020) (2021-03)
Walker, Colin
CactusWorld, 39(1) (pp. 79-80)

Pollination biology of Stenocereus queretaroensis and the importance of bat pollination services (2021-03)
Walker, Colin
CactusWorld, 39(1)

Two succulent mallows: Ceiba speciosa and Pseudobombax ellipticum (2021)
Walker, Colin
New Zealand Cactus & Succulent Journal, 74(1) (pp. 16-19)

Aloe kedongensis - a shrubby Kenyan endemic (2021)
Walker, Colin
Haworthiad, 35(1) (pp. 20-24)

Aloe tewoldei - a rare, cliff-dwelling Ethiopian endemic (2021)
Walker, Colin
Haworthiad, 35(1) (pp. 4-5)

Cactus & succulent books for children (2021)
Walker, Colin C. and Schultz, David
Cactus and Succulent Journal (US), 93(2) (pp. 197-204)

Aloidendron dichotomum. Der Urtyp der Baumaloe. The archetypal tree aloe (2021)
Walker, Colin
Avonia, 39(3) (pp. 210-219)

Aloe forbesii - a small Socotran endemic (2020-12)
Walker, Colin C.
CactusWorld, 38(4) (pp. 325-327)

Agave pablocarrilloi (2020-08)
Walker, Colin
New Zealand Cactus & Succulent Journal, 73(2) (pp. 13-15)

Aloidendron barberae: the largest tree aloe (2020-06)
Walker, Colin C.
CactusWorld, 38(2) (pp. 141-144)

Literature review. McCoy, Tom. The Aloes of Arabia (2020-06)
Walker, Colin
CactusWorld, 38(2) (pp. 154-155)

Literature review. Stutchbury, Ralph. Baobab [Book review] (2020-06)
Walker, Colin
CactusWorld, 38(2) (pp. 155-156)

Aloe cremnophila - a cliff-dwelling Somali endemic (2020-02-01)
Walker, Colin
Haworthiad, 34(1) (pp. 3-5)

Aloidendron barberae: the world's largest tree aloe observed in New Zealand and South Africa (2020-02)
Walker, Colin
New Zealand Cactus & Succulent Journal, 73(1) (pp. 17-21)

Filiferous agaves (2020)
Walker, Colin
CactusWorld, 38(1) (pp. 41-48)

Stapelia engleriana the "iceberg" species from Southern Africa (2020)
Walker, Colin
Asklepios, 126 (pp. 15-16)

Aloe huntleyana - a rare cliff-dwelling Namibian endemic (2020)
Walker, Colin
Haworthiad, 34(3) (pp. 78-81)

Contrasting growth habits of some arid-loving southern African aloes (2020)
Crook, Ivor; Pearcy, Les and Walker, Colin C.
Haworthiad, 34(3) (pp. 65-68)

The life and times of Gordon Rowley (1921-2019) (2019-12)
Walker, Colin
CactusWorld, 37(4) (pp. 257-262)

Two spectacularly spiny alluaudias (2019-11)
Walker, Colin
New Zealand Cactus & Succulent Journal, 72(3) (pp. 5-8)

Aloe spectabilis - a splendid South African species (2019-10)
Walker, Colin
Haworthiad, 33(3) (pp. 58-59)

Agave lophantha (2019-07)
Walker, Colin
New Zealand Cactus & Succulent Journal, 72(2) (pp. 15-17)

Kalanchoe arborescens - a Madagascan giant (2019-07)
Walker, Colin
Sedum Society Newsletter(130) (pp. 81-84)

Aloe elegans - an Ethiopian/Eritrean endemic? (2019-06)
Walker, Colin
Haworthiad, 33(2) (pp. 32-37)

Notes on the taxonomy, iconography, and ecology of Aloe pluridens Haw. (Asphodelaceae: Alooideae), an endemic species from southeastern South Africa (2019-05)
Walker, Colin C.; Smith, Gideon F. and Figueiredo, Estrela
Bradleya, 37 (pp. 60-72)

Two shrubby Madagascan kalanchoes (2019-02)
Walker, Colin C.
New Zealand Cactus & Succulent Journal, 72(1) (pp. 5-9)

Aloe erensii, Aloe jucunda and a new cultivar (2019)
Walker, Colin C. and Mace, Suzanne
CactusWorld, 37(1) (pp. 13-19)

Caputia tomentosa (2019)
Walker, Colin; Smith, G.F.; Crouch, N.R. and Condy, Gillian
Flowering Plants of Africa, 66 (pp. 168-178)

Aloidendron barberae (2019)
Walker, Colin; Smith, G.F.; Figueiredo, E.; Klopper, R.R.; Crouch, N.R. and Condy, Gillian
Flowering Plants of Africa, 66 (pp. 8-21)

Aloe bakeri - a critically endangered highly localised Madagascan endemic (2019)
Walker, Colin
CactusWorld, 37(3) (pp. 181-186)

Flowering of Agave nickelsiae (2018-12)
Walker, Colin C.
CactusWorld, 36(4) (pp. 290-291)

Two rare Bolivian endemic cacti (2018-12)
Walker, Colin C.
New Zealand Cactus & Succulent Journal, 71(3) (pp. 14-17)

Aloe littoralis - a review of this widespread African species (2018-10)
Walker, Colin C.
Haworthiad, 32(3) (pp. 60-64)

Two choice African Sansevierias: S. hargeisana and S. hallii (2018-06)
Walker, Colin C.
New Zealand Cactus & Succulent Journal, 71(2) (pp. 4-8)

Guest editorial (2018-06)
Walker, Colin C.
CactusWorld, 36(2) (p 88)

Aloe pearsonii - a unique species in habitat and in cultivation. (2018-03)
Walker, Colin C. and Vanden Bon, Alice
CactusWorld, 36(1) (pp. 33-40)

Echinocereus pensilis updated (2018-02)
Walker, Colin C.
New Zealand Cactus & Succulent Journal, 71(1) (pp. 14-15)

Stapelia gigantea - "der Goliath dieser Gattung" (2018)
Walker, Colin
Avonia, 36(2) (pp. 124-125)

The stapeliads of Philip Miller at the Chelsea Physic Garden (2018)
Walker, Colin C.
Asklepios, 125 (pp. 12-17)

Two stapelias: Stapelia gigantea and S. schinzii var. angolensis (2017-12)
Walker, Colin C.
New Zealand Cactus & Succulent Journal, 70(3) (pp. 6-8)

Two architectural agaves: A. victoriae-reginae and A. nickelsiae (2017-07)
Walker, Colin
Cactus and Succulent Journal of NSW, 31(1) (pp. 9-13)

Aloe tomentosa – eine Art mit ungewöhnlichen, behaarten Blüten aus dem Jemen (2017-07)
Walker, Colin C.
Sukkulenten, 103(7-8) (pp. 29-37)

Introducing the genus Phedimus (2017-06)
Walker, Colin C.
New Zealand Cactus & Succulent Journal, 70(2) (pp. 4-7)

A tale of two Ethiopian aloes: Aloe jacksonii & A. elkerriana (2017-06)
Walker, Colin C.
Haworthiad, 31(2) (pp. 31-32)

Aloe mitriformis subsp. distans: the small mitre aloe (2017-02)
Walker, Colin C.
New Zealand Cactus and Succulent Journal, 70(1) (pp. 4-7)

Aloe pulcherrima - a beautiful Ethiopian endemic (2017)
Walker, Colin C.
CactusWorld, 35(2) (pp. 131-135)

A new intergeneric hybrid: xGastonialoe 'Gordon Rowley' (2017)
Walker, Colin C.
CactusWorld, 35(1) (pp. 21-22)

Agave victoriae-reginae and its close relatives (2017)
Walker, Colin C.
CactusWorld, 35(3) (pp. 159-166)

My first flowering of Aloe reynoldsii (2017)
Walker, Colin C.
Haworthiad, 31(3) (pp. 70-71)

CactusTalk: More dragon tree tales (2017)
Walker, Colin C.
CactusWorld, 35(4) (pp. 287-288)

Aloe tomentosa - a species with unusual hairy flowers from the Yemen (2016-09)
Walker, Colin
CactusWorld, 34(3) (pp. 153-158)

Aloe vera on Lanzarote (2016)
Walker, Colin
New Zealand Cactus & Succulent Journal, 69(2) (pp. 20-23)

A couple of Curios (2016)
Walker, Colin C.
Northants News, 27(1) (pp. 5-7)

Beaucarnea updated (2015-09)
Walker, Colin
CactusWorld, 33(4) (pp. 267-272)

Eric Judd - South African Aloe artist (2015-03)
Walker, Colin and Smith, Gideon F.
CactusWorld, 33(1) (pp. 59-63)

Aloe succotrina (Asphodelaceae) (2015)
Walker, C. C.; Klopper, R. R.; Smith, G. F. and Condy, Gillian
Flowering Plants of Africa, 64 (pp. 26-40)

The origin and predominance of Aloe vera (2015)
Walker, Colin
CactusWorld, 33(4) (pp. 276-277)

Dasylirion wheeleri (2015)
Walker, Colin
Northants News, 26(3) (pp. 7-8)

Aloe hardyi - a rare South African cremnophyte (2014-12)
Walker, Colin
CactusWorld, 32(4) (pp. 289-292)

More changes in Haworthia. (2014-12)
Walker, Colin
CactusWorld, 32(4) (p 304)

More change in Aloe, Haworthia and their close relatives (2014-06)
Walker, Colin
CactusWorld, 32(2) (pp. 138-139)

All change in Dracaena and Sansevieria (2014-06)
Walker, Colin
CactusWorld, 32(2) (pp. 140-141)

All change in Aloe and Haworthia (2014-03-12)
Walker, Colin
Cactus and Succulent Journal of NSW, 29(4) (pp. 78-80)

The World's biggest cactus flowers (2014)
Walker, Colin and Thorburn, Marjorie
Northants News, 25(3) (pp. 12-13)

Aloe cremnophila and Aloe jacksonii - cliff-dwellers from the Horn of Africa. (2014)
Walker, Colin
Northants News, 25(2) (pp. 14-16)

All change in Aloe and Haworthia (2013-12)
Walker, Colin
CactusWorld, 31(4) (p 297)

Two Kenyan sansevierias of Peter Bally (2013-07)
Walker, Colin
Northants News, 24(2) (pp. 6-7)

A cholla cactus and a grasshopper (2012-12)
Walker, Colin
CactusWorld, 30(4) (pp. 233-234)

Agaves through the ages (2011-06)
Walker, Colin
Cactus and Succulent Journal of NSW, 27(8) (pp. 153-156)

The name game (2011-06)
Walker, Colin
Cactus and Succulent Journal of NSW, 27(8) (pp. 170-177)

Macaronesian memories. The succulents of the Canary Islands, Morocco and Madeira (2011-06)
Walker, Colin
Cactus and Succulent Journal of NSW, 27(8) (pp. 182-186)

What's in a name: an update on epithets used in Aloe L. (Asphodelaceae) (2011)
Smith, G.F.; Walker, Colin and Figueiredo, E.
Bradleya, 29 (pp. 179-181)

Gilbert Westacott Reynolds: his study of Aloe and a bibliography of his work (2010)
Walker, Colin
Bradleya, 28, (pp. 111-124)

Editorial: Darwin and Kew anniversaries (2009)
Walker, Colin
Bradleya, 27 (pp. 1-2)

A new name in Monsonia (2008-12)
Walker, Colin
CactusWorld, 26(4) (pp. 248-249)

Brachystelma bracteolatum Meve a rare Nigerian endemic (2008-12)
Walker, Colin C.
Asklepios, 103 (pp. 19-22)

Bradleya 25 and the Linnaean legacy (2007)
Walker, Colin C.
Bradleya, 25 (pp. 1-8)

A tale of two Arabian aloes (2005)
Walker, Colin
British Cactus & Succulent Journal, 23 (pp. 175-179)

xTavarorbea - another intergeneric hybrid stapeliad (2005)
Walker, Colin C.
Asklepios(92) (pp. 7-8)

Two succulent aroids (2004-12)
Walker, Colin
British Cactus & Succulent Journal, 22 (pp. 185-187)

A new intergeneric hybrid stapeliad (2004-11)
Walker, Colin
New Zealand Cactus & Succulent Journal, 57(4) (pp. 103-107 + cover)

James Harvey Callander and his rare publication: Cactus Culture for Amateurs (1906) (2002)
Walker, Colin
Cactus and Succulent Journal (US), 74(3) (pp. 121-126)

Introducing the Nolinaceae (2001-12)
Walker, Colin
British Cactus & Succulent Journal, 19(4) (pp. 214-221)

The botanical paintings of Mary Maud Page (2001)
Smith, Gideon F. and Walker, Colin C.
Bradleya, 19 (p 124)

Canaries and kasbahs - the succulents of the Canary Islands and Morocco - Part 2 (2000-08)
Walker, Colin C.
New Zealand Cactus & Succulent Journal, 53(3) (pp. 70-77)

Canaries and kasbahs - the succulents of the Canary Islands and Morocco (2000-05)
Walker, Colin C.
New Zealand Cactus & Succulent Journal, 53(2) (pp. 36-49)

John Medley Wood's Natal Asclepiads (2000-04)
Walker, Colin C. and Downs, Philip E.
Asklepios(79) (pp. 3-9)

Agave attenuata and some new cultivars (2000)
Walker, Colin C.
British Cactus & Succulent Journal, 18(2) (pp. 95-98)

Arabian asclepiads of Albert Deflers (1999-04)
Walker, Colin
Asklepios(76) (pp. 23-32)

A tale of dragons - the pachycaul species of Dracaena (1999)
Walker, Colin
British Cactus & Succulent Journal, 17(4) (pp. 171-177)

Senecio rowleyanus (1999)
Smith, G.F.; Walker, Colin and Condy, G.
Flowering Plants of Africa, 56 (pp. 116-120, t.2160)

A question of balance: when is a Caralluma a Caralluma and not a Caudanthera? (1997-12)
Walker, Colin
Asklepios(72) (pp. 12-13)

A.A. Bullock and his asclepiad studies (1997-12)
Walker, Colin
Asklepios(72) (pp. 20-24)

Van Rheede and the first Ceropegia (1997-08)
Walker, Colin
Asklepios(71) (pp. 26-34)

Obetia ficifolia - a pachycaul stinging nettle (1997)
Burston, Colin; Martin, Ralph and Walker, Colin
British Cactus & Succulent Journal, 15(1) (pp. 2-6)

James Donn and the succulents of 'Hortus Cantabrigiensis' (1996)
Walker, Colin C.
Bradleya, 14 (pp. 20-28)

Echeveria setosa var. deminuta (1994-09)
Walker, Colin
British Cactus & Succulent Journal, 12(3) (pp. 90-91)

Robert Brown's contributions to asclepiad study (1994-08)
Walker, Colin
Asklepios(62) (pp. 20-34, plate 1)

Frederick Scheer (1792-1868) of Kew (1994)
Walker, Colin C.
Kew Magazine, 11(2) (pp. 74-81)

Sansevierias make scents (1994)
Walker, Colin
British Cactus & Succulent Journal, 12 (p 92)

The Asclepiads of Morocco - a short commentary (1993-08)
Jonkers, Bert and Walker, Colin C.
Asklepios(59) (pp. 14-21)

Pilea peperomioides - a Chinese member of the stinging nettle family (1993)
Walker, Colin
British Cactus & Succulent Journal, 11(4) (pp. 98-99)

A note on the Carallumas of Jordan (1992)
Walker, Colin
Asklepios(55) (pp. 17-19)

The argan - multipurpose tree of Morocco (1992)
Prendergast, Hew D.V. and Walker, Colin C.
Kew Magazine, 9(2) (pp. 76-85)

Aloe dumetorum Mathew & Brandham - a dwarf Kenyan endemic (1991-06)
Walker, Colin C.
British Cactus & Succulent Journal, 9(2) (pp. 28-31)

Kleinia (Senecio) anteuphorbium (L.)Haw. - a Moroccan endemic (1991)
Walker, C. C. and Thorburn, M.
Aloe, 28(1) (pp. 18-22)

Pelargonium ceratophyllum L'Herit: the antler-leaved stork's bill (1990-09)
Walker, Colin C.
British Cactus & Succulent Journal, 8 (pp. 84-86)

Trichosacme lanata Zucc. - a woolly Mexican asclepiad (1990)
Walker, Colin
Asklepios, 51 (pp. 56-59)

Cussonia paniculata: the mountain cabbage tree (1988-12)
Walker, Colin C.
British Cactus & Succulent Journal, 6(4) (pp. 98-100)

xBrachypelia: a novel intergeneric hybrid (1988)
Walker, C. C.
Asklepios, 43 (pp. 83-86)

The euphorbias of Gran Canaria, Canary Islands (1987)
Walker, Colin C. and Thorburn, Marjorie
The Euphorbia Journal, 4 (pp. 32-47)

Pelargonium crassicaule L'Herit (1987)
Walker, C. C.
Aloe, 24(2) (pp. 32-34)

Dischidia - an obscure organism? (1987)
Walker, Colin
Asklepios, 40 (pp. 75-80)

More on Dischidia (1986)
Walker, Colin
Asklepios, 38 (pp. 11-13)

Adenia glauca: a 'lump' with an interesting life-style (1985-03)
Walker, Colin C.
British Cactus & Succulent Journal, 3(1) (pp. 18-20)

Dischidia: an introduction to asclepiad ant plants (1985)
Walker, C. C.
Asklepios, 35 (pp. 3-11)

Cremnophila nutans: A Sedum under another name? (1984)
Walker, C. C.
British Cactus & Succulent Journal, 2(4) (pp. 100-103)

Sarcostemma: leafless succulent lianas (1983)
Walker, C.C.
Asklepios, 29 (pp. 18-21)

The ciliated Orbea (1983)
Walker, C.C.
Asklepios, 27 (pp. 59-63)

Brachystelma: an introduction and checklist (1982)
Walker, C. C.
Asklepios, 25 (pp. 92-106)

A new name in Brachystelma (1981)
Walker, Colin
Asklepios, 24 (pp. 66-67)

More on Tridentea Haw (1980)
Walker, Colin
Asclepiadaceae, 20 (pp. 7-10)

Aloes – The definitive guide (2011)
Carter, S.; Lavranos, J. J.; Newton, L. E. and Walker, C. C.
ISBN : 9781842464397 | Publisher : Kew Publishing in association with the British Cactus and Succulent Society | Published : London

Malvaceae (2023-05-03)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 801-806)
ISBN : 978-3-030-93491-0 | Publisher : Springer, Cham

Adansonia MALVACEAE (2023-05-03)
Walker, C. C. and Eggli, U.
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 807-820)
ISBN : 978-3-030-93491-0 | Publisher : Springer, Cham

Brachychiton MALVACEAE (2023-05-03)
Forster, P. I.; Guymer, G. P. and Walker, C. C.
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 821-825)
Publisher : Springer, Cham

Cavanillesia MALVACEAE (2023-05-03)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 827-833)
ISBN : 978-3-030-93491-0 | Publisher : Springer, Cham

Ceiba MALVACEAE (2023-05-03)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 835-841)
ISBN : 978-3-030-93491-0 | Publisher : Springer, Cham

Megistostegium MALVACEAE (2023-05-03)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 834-845)
ISBN : 978-3-030-93491-0 | Publisher : Springer Nature | Published : Switzerland

Sterculia MALVACEAE (2023-05-03)
Forster, P. I.; Guymer, G. P.; Van Jaarsveld, E. J. and Walker, C. C.
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 853-858)
ISBN : 978-3-030-93492-7 | Publisher : Springer, Cham

Urticaceae (2023-05-03)
Walker, C. C. and Eggli, U.
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 1071-1074)
ISBN : 978-3-030-93492-7 | Publisher : Springer, Cham

Obetia URTICACEAE (2023-05-03)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 1077-1078)
ISBN : 978-3-030-93491-0 | Publisher : Springer, Cham

Pilea URTICACEAE (2023-05-03)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 1079-1084)
ISBN : 978-3-030-93491-0 | Publisher : Springer, Cham

Pseudobombax Malvaceae (2023)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 847-852)
ISBN : 978-3-030-93491-0 | Publisher : Springer Nature | Published : Switzerland

Laportea Urticaceae (2023)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 1075-1076)
ISBN : 978-3-030-93491-0 | Publisher : Springer Nature | Published : Switzerland

Ceiba MALVACEAE (2022-06-30)
Walker, Colin
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants
Publisher : Springer | Published : Cham

Adansonia MALVACEAE (2022-06-29)
Walker, Colin
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (pp. 807-820)
Publisher : Springer | Published : Cham

Obetia URTICACEAE (2022-06-25)
Walker, C.C.
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (SUCCPLANTS)
ISBN : 978-3-030-85239-9 / 978-3-030-85239-9 | Publisher : Springer, Cham | Published : Switzerland

Pilea URTICACEAE (2022-06-25)
Walker, Colin
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants
Publisher : Springer | Published : Cham

Brachychiton MALVACEAE (2022-06-25)
Walker, Colin; Forster, P.I.; Guymer, G.P. and van Jaarsveld, E.J.
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants
Publisher : Springer | Published : Cham

Malvaceae (2022-06-16)
Walker, Colin
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants (2nd ed.)
Publisher : Springer | Published : Cham

Laportea URTICACEAE (2022-06-09)
Walker, C. C.
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants
Publisher : Springer | Published : Cham

Megistostegium MALVACEAE (2022-05-12)
Walker, Colin
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants
Publisher : Springer | Published : Cham

Pseudobombax MALVACEAE (2022-05-06)
Walker, Colin
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants
Publisher : Springer | Published : Cham

Cavanillesia Malvaceae (2022-05-05)
Walker, C. C.
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants(2nd. ed.)
Publisher : Springer | Published : Cham

Sterculia MALVACEAE (2022-04-26)
Forster, P.I.; Guymer, G.P.; Van Jaarsveld, E.J. and Walker, C.C.
In: Eggli, Urs and Nyffeler, Reto eds. Dicotyledons: Rosids. Illustrated Handbook of Succulent Plants, 2nd ed
ISBN : 978-3-030-85239-9 | Publisher : Springer | Published : Cham

Urticaceae (2022-02-05)
Walker, C.C. and Eggli, U.
In: Eggli, U. and Nyffeler, R. eds. Dicotyledons: Rosids (2nd ed). Illustrated Handbook of Succulent Plants
ISBN : 978-3-030-93491-0 / 978-3-030-85239-9 | Publisher : Springer International Publishing | Published : Cham

Beaucarnea Ruscaceae (2020)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants (2nd ed.) (pp. 1319-1328)
ISBN : 978-3-662-56484-4 | Publisher : Springer Reference | Published : Berlin

Dasylirion Ruscaceae (2020)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants (2nd ed.) (pp. 1329-1335)
ISBN : 978-3-662-56484-4 | Publisher : Springer Reference | Published : Berlin

Dracaena Ruscaceae (2020)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants (pp. 1337-1344)
ISBN : 978-3-662-56484-4 | Publisher : Springer Reference | Published : Berlin

Nolina Ruscaceae (2020)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants (2nd ed.) (pp. 1345-1351)
ISBN : 978-3-662-56484-4 | Publisher : Springer Reference | Published : Berlin

Laxmanniaceae (2020)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants (2nd ed.) (pp. 1293-1294)
ISBN : 978-3-662-56484-4 | Publisher : Springer Reference | Published : Berlin

Cordyline Laxmanniaceae (2020)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants (2nd ed.) (pp. 1295-1296)
ISBN : 978-3-662-56484-4 | Publisher : Springer Reference | Published : Berlin

Foreword (2019)
Walker, Colin
In: Smith, Gideon F.; Figueiredo, Estrela and van Wyk, Abraham E. eds. Kalanchoe (Crassulaceae) in Southern Africa (ix-x)
ISBN : 978-0-12-814007-9 | Publisher : Academic Press (Elsevier) | Published : London

Beaucarnea RUSCACEAE (2018-11)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants
ISBN : 978-3-662-56484-4 | Publisher : Springer Verlag | Published : Berlin, etc.

Nolina RUSCACEAE (2018-10-08)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants
ISBN : 978-3-662-56324-3 | Publisher : Springer Verlag | Published : Berlin

Dracaena RUSCACEAE (2018-07-04)
Walker, C. C.
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants (SUCCPLANTS)
Publisher : Springer Verlag

Cordyline LAXMANNIACEAE (2018-06-14)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants
ISBN : 978-3-662-56324-3 | Publisher : Springer Verlag | Published : Berlin

Laxmanniaceae (2018-06-14)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants
ISBN : 978-3-662-56324-3 | Publisher : Springer Verlag | Published : Berlin

Dasylirion (Ruscaceae) (2018-06-14)
Walker, Colin
In: Eggli, Urs and Nyffeler, Reto eds. Monocotyledons. Illustrated Handbook of Succulent Plants
ISBN : 978-3-662-56324-3 | Publisher : Springer Verlag | Published : Berlin

Foreword (2011)
Walker, Colin
In: Craib, Charles and Lavranos, John eds. The Bushman Candles (x-xi)
ISBN : 978-0-620-48776-4 | Publisher : Penrock Publications | Published : Bryanston, South Africa

Crassulaceae (Umbilicus) (2003)
Walker, Colin
In: Eggli, Urs ed. Crassulaceae. Illustrated Handbook of Succulent Plants (6) (pp. 364-367)
ISBN : 3-540-41965-9 | Publisher : Springer-Verlag | Published : Berlin

Asteraceae (Baeriopsis) (2002)
Walker, Colin
In: Eggli, Urs ed. Dicotyledons. Illustrated Handbook of Succulent Plants (p 20)
ISBN : 3-540-41966-7, 978-3-540-41966-2 | Publisher : Springer-Verlag | Published : Berlin

Bombacaceae (Adansonia, Cavanillesia, Ceiba, Pseudobombax) (2002)
Walker, Colin
In: Eggli, Urs ed. Dicotyledons. Illustrated Handbook of Succulent Plants (4) (pp. 48-52)
ISBN : 3-540-41966-7 | Publisher : Springer-Verlag | Published : Berlin

Oxalidaceae (Oxalis) (2002)
Walker, Colin
In: Eggli, Urs ed. Dicotyledons. Illustrated Handbook of Succulent Plants (pp. 333-336)
ISBN : 3-540-41966-7 | Publisher : Springer-Verlag | Published : Berlin

Urticaceae (Laportea, Obetia, Pilea) (2002)
Walker, Colin
In: Eggli, Urs ed. Dicotyledons. Illustrated Handbook of Succulent Plants (4) (pp. 447-450)
ISBN : 3-540-41966-7 | Publisher : Springer-Verlag | Published : Berlin

Urticaceae (Laportea, Obetia, Pilea) (2002)
Walker, Colin
In: Eggli, Urs ed. Zweikeimblaettrige Pflanzen (Dicotyledonen).. Sukkulenten-Lexikon (pp. 478-480)
ISBN : 3-8001-3915-4 | Publisher : Verlag Eugen Ulmer | Published : Stuttgart

Dracaenaceae (Cordyline, Dracaena) (2001)
Walker, Colin
In: Eggli, Urs ed. Monocotyledons. Illustrated Handbook of Succulent Plants (1) (pp. 258-261)
ISBN : 3-540-41692-7 | Publisher : Springer-Verlag | Published : Berlin

Nolinaceae (Beaucarnea, Calibanus, Dasylirion, Nolina) (2001)
Walker, Colin
In: Eggli, Urs ed. Monocotyledons. Illustrated Handbook of Succulent Plants (1) (pp. 286-292)
ISBN : 3-540-41692-7 | Publisher : Springer-Verlag | Published : Berlin

A history of succulent exploration in East and North-East Africa (2004)
Walker, Colin
In : Proceedings of the International Symposium: The Succulent Plants of Eastern Africa: History, Botanical Exploration and Research, (20-22 Sep 2002, Rome, Italy)