As Alec Holland

Swamp Thing Vol. 4 #19 (November 2005) "The Holland Mind" [Flashback]
Swamp Thing Vol. 2 #126 (December 1992): "The Big Picture" [Flashback]
Swamp Thing Vol. 4 #15 (July 2005) "Healing the Breach, Chapter I-The Emotional Hostage" [Flashback]
Swamp Thing Vol. 4 #16 (August 2005) "Healing the Breach, Chapter II-Where The Rushing Waters Go" [Flashback]
Swamp Thing Vol. 4 #17 (September 2005) "Healing the Breach, Chapter III-While Sinking" [Flashback]
Swamp Thing Vol. 4 #18 (October 2005) "Healing the Breach, Chapter IV-Seeding Madness" [Flashback]
Swamp Thing Vol. 4 #19 (November 2005) "The Holland Mind" [Flashback]
Swamp Thing Vol. 1 #1 (October-November 1972): "Dark Genesis" [Flashback]
Saga of the Swamp Thing #1 (May 1982): "What Peace There May Be In Silence" [Flashback]
Swamp Thing Vol. 1 #1 (October-November 1972): "Dark Genesis" [Flashback]
Saga of the Swamp Thing #28 (September 1984): "The Burial" [Flashback]
Swamp Thing Vol. 2 #104 (February 1991): "The Quest for the Elementals I: Matango" [Flashback]
Saga of the Swamp Thing #1 (May 1982): "What Peace There May Be In Silence" [Flashback]
Swamp Thing Vol. 1 #1 (October-November 1972): "Dark Genesis" [Flashback]
Saga of the Swamp Thing #28 (September 1984): "The Burial" [Flashback]
Saga of the Swamp Thing #21 (February 1984): "The Anatomy Lesson" [Flashback]

As Swamp Thing

Saga of the Swamp Thing #21 (February 1984): "The Anatomy Lesson" [Flashback]
Swamp Thing Vol. 1 #1 (October-November 1972): "Dark Genesis"
Saga of the Swamp Thing #1 (May 1982): "What Peace There May Be In Silence" [Flashback]
Swamp Thing Vol. 1 #1 (October-November 1972): "Dark Genesis"
Swamp Thing Vol. 1 #2 (December 1972-January 1973): "The Man Who Wanted Forever"

As Alec Holland

Swamp Thing Vol. 1 #2 (December 1972-January 1973): "The Man Who Wanted Forever"

As Swamp Thing

Swamp Thing Vol. 1 #2 (December 1972-January 1973): "The Man Who Wanted Forever"
Swamp Thing Vol. 1 #3 (February-March 1973): "The Patchwork Man"
House of Secrets #140 (February-March 1976) "Reprise-The Patchwork Man" [Flashback]
Swamp Thing Vol. 1 #3 (February-March 1973): "The Patchwork Man"
Swamp Thing Vol. 1 #4 (April-May 1973): "Monster on the Moors"
Swamp Thing Vol. 1 #5 (July-August 1973): "Last of the Ravenwind Witches"
Swamp Thing Vol. 1 #19 (October 1975): "A Second Time to Die" [Flashback]
Swamp Thing Vol. 1 #5 (July-August 1973): "Last of the Ravenwind Witches"
Swamp Thing Vol. 1 #6 (September-October 1973): "A Clockwork Horror"
Swamp Thing Vol. 1 #7 (November-December 1973): "Night of the Bat"
Swamp Thing Vol. 1 #17 (July 1975): "The Destiny Machine" [Flashback]
Swamp Thing Vol. 1 #8 (January-February 1974): "The Lurker In Tunnel 13"
All-New Atom #3 (November 2006): "My Life In Miniature: Part Three - Binding Energies" [Flashback]
Challengers of the Unknown Vol. 1 #82 (August-September 1977): "The Lurker Below" [Flashback]
Swamp Thing Vol. 1 #8 (January-February 1974): "The Lurker In Tunnel 13"
Swamp Thing Vol. 1 #9 (March-April 1974): "The Stalker From Beyond"
Swamp Thing Vol. 1 #10 (May-June 1974): "The Man Who Would Not Die"
Swamp Thing Vol. 1 #11 (July-August 1974): "The Conqueror Worms"
Swamp Thing Vol. 1 #12 (September-October 1974): "The Eternity Man"
Swamp Thing Vol. 1 #13 (November-December 1974): "The Leviathan Conspiracy"
Saga of the Swamp Thing #1 (May 1982): "What Peace There May Be In Silence" [Flashback]
Swamp Thing Vol. 1 #13 (November-December 1974): "The Leviathan Conspiracy"
Swamp Thing Vol. 1 #14 (January-February 1975): "The Tomorrow Children"
Swamp Thing Vol. 1 #15 (March-April 1975): "The Soul-Spell of Father Bliss"
Swamp Thing Vol. 1 #16 (May 1975): "Night of the Warring Dead"
Swamp Thing Vol. 1 #17 (July 1975): "The Destiny Machine"
Swamp Thing Vol. 1 #18 (September 1975): "Village of the Doomed"
Brave and the Bold #122 (October 1975): "The Hour of the Beast"
Swamp Thing Vol. 1 #19 (October 1975): "A Second Time to Die"
Swamp Thing Vol. 1 #20 (December 1975-January 1976): "The Mirror Monster"
Swamp Thing Vol. 1 #21 (February-March 1976): "Requiem"
Swamp Thing Vol. 1 #22 (April-May 1976): "The Solomon Plague"
Swamp Thing Vol. 1 #23 (June-July 1976): "Rebirth and Nightmare"

As Alec Holland

Swamp Thing Vol. 1 #23 (June-July 1976): "Rebirth and Nightmare"
Swamp Thing Vol. 1 #24 (August-September 1976): "The Earth Below"
Challengers of the Unknown Vol. 1 #83 (October-November 1977): "Seven Doorways to Destiny"

As Swamp Thing

Challengers of the Unknown Vol. 1 #83 (October-November 1977): "Seven Doorways to Destiny"
Challengers of the Unknown Vol. 1 #84 (December 1977-January 1978): "To Save a Monster"
Challengers of the Unknown Vol. 1 #85 (February-March 1978): "The Creature from the End of Time"
Challengers of the Unknown Vol. 1 #86 (April-May 1978): "The War at Time's End"
Challengers of the Unknown Vol. 1 #87 (June-July 1978): "Twelve Million Years to Twilight"
Infinity, Inc. Vol. 1 #39 (June 1987): "The Saga of Solomon Grundy" [Flashback]
DC Comics Presents #8 (April 1979): "The Sixty Deaths of Solomon Grundy"
Brave and the Bold #176 (July 1981): "The Delta Connection"
Saga of the Swamp Thing #1 (May 1982): "What Peace There May Be In Silence"
Saga of the Swamp Thing #2 (June 1982): "Something To Live For"
Saga of the Swamp Thing #3 (July 1982): "A Town Has Turned To Blood"
Saga of the Swamp Thing #4 (August 1982): "In the White Room"
Saga of the Swamp Thing #5 (September 1982): "The Screams of Hungry Flesh"
Saga of the Swamp Thing #6 (October 1982): "Sins on the Water"
Saga of the Swamp Thing #7 (November 1982): "I Have Seen the Splintered Timber of a Hundred Shattered Hulls"
Saga of the Swamp Thing #8 (December 1982): "Here's Looking At You, Kid"
Saga of the Swamp Thing #9 (January 1983): "Prelude To Holocaust"
Saga of the Swamp Thing #10 (February 1983): "Number of the Beast"
Saga of the Swamp Thing #11 (March 1983): "Heart of Stone, Feet of Clay"
Saga of the Swamp Thing #12 (April 1983): "And Yet It Lives"
Saga of the Swamp Thing #13 (May 1983): "Lambs To the Slaughter"
Saga of the Swamp Thing #14 (June 1983): "Crystal Visions, Shattered Dreams!"
Saga of the Swamp Thing #15 (July 1983): "Empires Made of Sand"
Saga of the Swamp Thing #16 (August 1983): "Stopover in a Place of Secret Truths"

As Alec Holland

Saga of the Swamp Thing #16 (August 1983): "Stopover in a Place of Secret Truths"

As Swamp Thing

Saga of the Swamp Thing #16 (August 1983): "Stopover in a Place of Secret Truths"
Saga of the Swamp Thing #17 (October 1983): "...And Things That Go Bump in the Night"
Saga of the Swamp Thing #18 (November 1983): "The Man Who Would Not Die"
Saga of the Swamp Thing #19 (December 1983): "And the Meek Shall Inherit..."
Saga of the Swamp Thing #20 (January 1984): "Loose Ends"
Saga of the Swamp Thing #21 (February 1984): "The Anatomy Lesson"
Saga of the Swamp Thing #22 (March 1984): "Swamped"
Saga of the Swamp Thing #23 (April 1984): "Another Green World"
Saga of the Swamp Thing #24 (May 1984): "Roots"
Saga of the Swamp Thing #25 (June 1984): "The Sleep of Reason"
Saga of the Swamp Thing #26 (July 1984): "A Time Of Running"
Saga of the Swamp Thing #27 (August 1984): "By Demons Driven"
Saga of the Swamp Thing #28 (September 1984): "The Burial"
Saga of the Swamp Thing #29 (October 1984): "Love and Death"
Saga of the Swamp Thing #30 (November 1984): "A Halo of Flies"
Saga of the Swamp Thing #31 (December 1984): "The Brimstone Ballet"
Saga of the Swamp Thing Annual #2 (1984): "Down Amongst the Dead Men"
Saga of the Swamp Thing #32 (January 1985): "Pog"
Saga of the Swamp Thing #34 (March 1985): "Rite of Spring"
Saga of the Swamp Thing #35 (April 1985): "The Nukeface Papers, Part 1"
Saga of the Swamp Thing #36 (May 1985): "The Nukeface Papers, Part 2"
Saga of the Swamp Thing #37 (June 1985): "Growth Patterns"
Saga of the Swamp Thing #38 (July 1985): "Still Waters"
Saga of the Swamp Thing #39 (August 1985): "Fish Story"
DC Comics Presents #85 (September 1985): "The Jungle Line"
Saga of the Swamp Thing #40 (September 1985): "The Curse"
Saga of the Swamp Thing #44 (January 1986): "Bogeymen"
Swamp Thing Vol. 2 #55 (December 1986): "Earth to Earth" [Flashback]
Saga of the Swamp Thing #45 (February 1986): "Ghost Dance"
Swamp Thing Vol. 2 #46 (March 1986): "Revelations" [Pages 1-7]
Crisis on Infinite Earths #5 (August 1985): "Worlds in Limbo" [Appearance same in part as Swamp Thing #46, pages 8-10]
Legends of the DC Universe: Crisis on Infinite Earths (February 1999): "The Untold Story"
JLA: Incarnations #5 (November 2001): "Crisis"
Swamp Thing Vol. 2 #46 (March 1986): "Revelations" [Pages 11-22]
Crisis on Infinite Earths #10 (January 1986): "Death at the Dawn of Time!" [Flashback]
Saga of the Swamp Thing #41 (October 1985): "Southern Change"
Saga of the Swamp Thing #42 (November 1985): "Strange Fruit"
Saga of the Swamp Thing #43 (December 1985): "Windfall"
Swamp Thing Vol. 2 #47 (April 1986): "The Parliament of Trees"
Swamp Thing Vol. 2 #48 (May 1986): "A Murder of Crows"
Swamp Thing Vol. 2 #49 (June 1986): "The Summoning"
Swamp Thing Vol. 2 #50 (July 1986): "The End"
Swamp Thing Vol. 2 #51 (August 1986): "Home Free"
Swamp Thing Vol. 2 #52 (September 1986): "Natural Consequences"
Swamp Thing Vol. 2 #53 (October 1986): "Garden of Earthly Delights"
Swamp Thing Vol. 2 #55 (December 1986): "Earth to Earth"
Swamp Thing Vol. 2 #56 (January 1987): "My Blue Heaven"
Martian Manhunter Vol. 2 #11 (October 1999) "Pilgrims" [Flashback]
Swamp Thing Vol. 2 #57 (February 1987): "Mysteries in Space"
Swamp Thing Vol. 2 #58 (March 1987): "Exiles"
Swamp Thing Vol. 2 #60 (May 1987): "Loving the Alien"
Swamp Thing Vol. 2 #61 (June 1987): "All Flesh is Grass"
Swamp Thing Vol. 2 #62 (July 1987): "Wavelength"
Swamp Thing Vol. 2 #63 (August 1987): "Loose Ends (Reprise)"
Swamp Thing Vol. 2 #64 (September 1987): "Return of the Good Gumbo"
Swamp Thing Vol. 2 #65 (October 1987): "(We Could Be) Diving for Pearls"
Swamp Thing Annual Vol. 2 #3 (1987): "Distant Cousins"
Swamp Thing Vol. 2 #66 (November 1987): "One Flew Over the Cuckoo's Nest"
Swamp Thing Vol. 2 #67 (December 1987): "The Wisdom of Solomon"
Swamp Thing Vol. 2 #68 (January 1988): "Reflections In a Golden Eye"
Swamp Thing Vol. 2 #69 (February 1988): "Wild Thing"
Infinity, Inc. Vol. 1 #46 (January 1988): "Swamped"
Millennium #8 (February 1988): "The Rising and Advancing of Ten Spirits"
Swamp Thing Vol. 2 #70 (March 1988): "The Secret Life of Plants"
Swamp Thing Vol. 2 #71 (April 1988): "Fear of Flying"
Swamp Thing Vol. 2 #72 (May 1988): "Gargles In the Rat Race Choir"
Captain Atom #16 (June 1988): "The Big Blowout"
Captain Atom #17 (July 1988): "Battle Beyond the Green"
Swamp Thing Vol. 2 #73 (June 1988): "The Fire Next Door"
Swamp Thing Vol. 2 #74 (July 1988): "Center of the Cyclone"
Swamp Thing Vol. 2 #75 (August 1988): "The Thinker"
Hellblazer #9 (September 1988): "Shot To Hell"
Swamp Thing Vol. 2 #76 (September 1988): "L'adoration De La Terre"
Hellblazer #10 (October 1988): "Sex and Death"
Swamp Thing Vol. 2 #77 (October 1988): "Infernal Triangles"
Swamp Thing Vol. 2 #78 (November 1988): "To Sow One's Seed In the Wind"
Swamp Thing Annual Vol. 2 #4 (October 1988): "Threads"
Black Orchid Vol. 1 #3 (February 1989): "Yes..."
Black Orchid Vol. 2 #9 (May 1994): "The Murmuring of Mists, the Whispering of Flowers" [Flashback]
Black Orchid Vol. 1 #3 (February 1989): "Yes..."
Swamp Thing Vol. 2 #79 (December 1988): "Waiting For God (Oh!)"
Swamp Thing Vol. 2 #80 (Winter 1988): "The Longest Day"
Swamp Thing Vol. 2 #82 (January 1989): "Brothers In Arms Part Two"
Swamp Thing Vol. 2 #83 (February 1989): "Brothers In Arms Part One"
Swamp Thing Vol. 2 #85 (April 1989): "My Name Is Nobody"
Swamp Thing Vol. 2 #86 (May 1989): "Heroes of the Revolution"
Swamp Thing Vol. 2 #87 (June 1989): "Fall of the House of Pendragon"
Swamp Thing Vol. 2 #88 (September 1989): "Survival of the Fittest"
Swamp Thing Vol. 2 #89 (November 1989): "Founding Fathers"
Swamp Thing Vol. 2 #90 (December 1989): "Journeys"
Swamp Thing Vol. 3 #2 (June 2000) "A Tree Falls In the Forest" [Flashback]
Firestorm, The Nuclear Man #90 (October 1989): "The Elemental War, Part 1: Force of Nature"
Firestorm, The Nuclear Man #91 (November 1989): "The Elemental War, Part 2: Confrontation"
Firestorm, The Nuclear Man #92 (December 1989): "The Elemental War, Part 3: Vision"
Firestorm, The Nuclear Man #93 (January 1990): "The Elemental War, Conclusion: Storm Front"
Swamp Thing Vol. 2 #91 (January 1990): "Augurs and Offerings"
Swamp Thing Vol. 2 #92 (February 1990): "La Terre qui Disparaît"
Swamp Thing Vol. 2 #93 (March 1990): "Capturing the Moments of Your Life"
Swamp Thing Vol. 2 #94 (April 1990): "The Mysterious Axman's Jazz"
Swamp Thing Vol. 2 #95 (May 1990): "Toxic Wonderland"
Swamp Thing Vol. 2 #96 (June 1990): "Hell To Pay"
Swamp Thing Vol. 2 #97 (July 1990): "Scattered Houses"
Swamp Thing Vol. 2 #98 (August 1990): "Family Reunion"
Swamp Thing Vol. 2 #99 (September 1990): "Leaves In A Tempest"
Swamp Thing Vol. 2 #100 (October 1990): "Tales of Eden"
Swamp Thing Vol. 2 #102 (December 1990): "And All the King's Horses..."
Swamp Thing Vol. 2 #103 (January 1991): "Exodus"
Swamp Thing Vol. 2 #104 (February 1991): "The Quest for the Elementals I: Matango"
Swamp Thing Vol. 2 #105 (March 1991): "The Quest for the Elementals II: Living Sacrifices"
Swamp Thing Vol. 2 #106 (April 1991): "The Quest for the Elementals III: Dead Tribes and Forgotten Souls"
Swamp Thing Vol. 2 #107 (May 1991): "The Quest for the Elementals IV: Stabs of Life Echoing In A Void"
Swamp Thing Vol. 2 #108 (June 1991): "The Quest for the Elementals V: Siege"
Swamp Thing Vol. 2 #109 (July 1991): "The Quest for the Elementals VI: A Descent of Shadows"
Swamp Thing Annual Vol. 2 #6 (1991): "Les Perdu"
Swamp Thing Vol. 2 #110 (August 1991): "Any Deadly Thing"
Swamp Thing Vol. 2 #111 (September 1991): "Zydeco Ya-Ya"
Swamp Thing Vol. 2 #112 (October 1991): "All the Swamp King's Men"
Swamp Thing Vol. 2 #113 (November 1991): "Fear and Loathing On the Bayou Trail"
Swamp Thing Vol. 2 #114 (December 1991): "Pirate's Alley"
Swamp Thing Vol. 2 #115 (January 1992): "Rum, Necromancy, & the Lash"
Swamp Thing Vol. 2 #117 (March 1992): "The Lord of Misrule"
Swamp Thing Vol. 2 #118 (April 1992): "A Child's Garden"
Ambush Bug Nothing Special #1 (September 1992): "Don't Lose Sight of the Forest for the Trees" [Flashback]
Swamp Thing Vol. 2 #118 (April 1992): "A Child's Garden"
Swamp Thing Vol. 2 #119 (May 1992): "The Bad Man"
Swamp Thing Vol. 2 #120 (June 1992): "Lady Jane"
Swamp Thing Vol. 2 #121 (July 1992): "Laissez Les Bon Temps Rulers"
Swamp Thing Vol. 2 #122 (August 1992): "The Eye of the Needleman"
Swamp Thing Vol. 2 #123 (September 1992): "Punctures"
Swamp Thing Vol. 2 #124 (October 1992): "Husks"
Swamp Thing Vol. 2 #125 (November 1992): "Family Reunion"
Swamp Thing Vol. 2 #126 (December 1992): "The Big Picture"
New Titans Annual #9 (July 1993): "The Red Hand Blues"
Hellblazer #63 (March 1993): "Forty"
Swamp Thing Vol. 2 #127 (January 1993): "Project Proteus"
Swamp Thing Vol. 2 #128 (February 1993): "Toxic Shock"
Swamp Thing Vol. 2 #129 (March 1993): "Swamp Fever"
Swamp Thing Vol. 2 #130 (April 1993): "Home Sick"
Swamp Thing Vol. 2 #131 (May 1993): "Folk Remedy"
Swamp Thing Vol. 2 #132 (June 1993): "Home Body"
Swamp Thing Vol. 2 #133 (July 1993): "Daisy Chain"
Swamp Thing Vol. 2 #134 (August 1993): "She's Leaving Houma"
Vertigo Jam #1 (August 1993): "The Ghost In the Green"
Swamp Thing Vol. 2 #134 (August 1993): "She's Leaving Houma"
Swamp Thing Vol. 2 #135 (September 1993): "Marital Problems"
Swamp Thing Vol. 2 #136 (October 1993): "Cross-Pollination"
Swamp Thing Vol. 2 #137 (November 1993): "Dead Relatives"
Swamp Thing Vol. 2 #138 (December 1993): "And In the End..."
Swamp Thing Vol. 3 #9 (January 2001): "Concrete Jungle, Part Three--Forget Me Not" [Flashback]
Swamp Thing Vol. 2 #138 (December 1993): "And In the End..."
Black Orchid Vol. 2 #5 (January 1994): "The Mind Fields Part One"
Swamp Thing Vol. 2 #139 (January 1994): "The Mind Fields Part Two"

As Alec Holland

Swamp Thing Vol. 2 #140 (March 1994): "Vegetable Man"
Swamp Thing Vol. 2 #141 (April 1994): "Bad Gumbo"
Swamp Thing Vol. 2 #142 (May 1994): "Soul Train"
Swamp Thing Vol. 2 #143 (June 1994): "Desert Hearts"

As Swamp Thing

Swamp Thing Vol. 2 #143 (June 1994): "Desert Hearts"
Swamp Thing Vol. 2 #144 (July 1994): "A Hope In Hell"
Swamp Thing Vol. 2 #145 (August 1994): "Big Game"
Swamp Thing Vol. 2 #146 (September 1994): "Murder In the Dark"
Swamp Thing Vol. 2 #147 (October 1994): "Amsterdamnation"
Swamp Thing Vol. 2 #148 (November 1994): "Feeding Habits"
Swamp Thing Vol. 2 #149 (December 1994): "The Root of All Evil"
Swamp Thing Vol. 2 #150 (January 1995): "The Illumination"
Guy Gardner: Warrior #29 (March 1995): "It's My Party And I'll Fight If I Want To"
Swamp Thing Vol. 2 #151 (February 1995): "River Run Prologue: Flotsam and Jetsam"
Swamp Thing Vol. 2 #152 (March 1995): "River Run Ch. 1: City of the Dead"
Swamp Thing Vol. 2 #153 (April 1995): "River Run Ch. 2: Twillight of the Gods"
Swamp Thing Vol. 2 #154 (May 1995): "River Run Ch. 3: The Bad Seed"
Swamp Thing Vol. 2 #155 (June 1995): "River Run Ch. 4: The Secret of Slaughter Swamp"
Swamp Thing Vol. 2 #156 (July 1995): "River Run Ch. 5: Darker Genesis"
Swamp Thing Vol. 2 #157 (August 1995): "River Run Ch. 6: Sink Or Swim"
Swamp Thing Vol. 2 #158 (September 1995): "River Run Ch. 7: The Parliament of Waves"
Batman #521 (August 1995): "Killer Croc-Fast Train to the Wet Dark"
Batman #522 (September 1995): "Swamp Things"
Swamp Thing Vol. 2 #160 (November 1995): "Ace of Swords"
Swamp Thing Vol. 2 #161 (December 1995): "Many Happy Returns"
Swamp Thing Vol. 4 #9 (January 2005): "Love in Vain, Chapter One" [Flashback]
Swamp Thing Vol. 2 #161 (December 1995): "Many Happy Returns"
Swamp Thing Vol. 2 #162 (January 1996): "Telephone Calls From The Dead"
Underworld Unleashed: Abyss - Hell's Sentinel #1 (December 1995): "Hell's Sentinel"
Guy Gardner: Warrior #39 (February 1996): "Merriment, Mistletoe, and Mayhem!"
Swamp Thing Vol. 2 #163 (February 1996): "Trees of Knowledge"
Swamp Thing Vol. 2 #164 (March 1996): "The Parliament of Vapors"
Batman: Shadow of the Bat #57 (December 1996): "Leaves of Grass, Part 2: Reefer Madness" [Flashback]
Swamp Thing Vol. 2 #166 (May 1996): "Trial By Fire, Part 1: Golden Days Before The End"
Swamp Thing Vol. 2 #167 (June 1996): "Trial By Fire, Part 2: The Word of God"
Swamp Thing Vol. 2 #168 (July 1996): "Trial By Fire, Part 3: Last Temptation of Anton"
Swamp Thing Vol. 2 #169 (August 1996): "Trial By Fire, Part 4: Judas Tree"

As Alec Holland

Swamp Thing Vol. 2 #169 (August 1996): "Trial By Fire, Part 4: Judas Tree"
Swamp Thing Vol. 2 #170 (September 1996): "Trial By Fire, Part 5: Apocalypse Now"

As Swamp Thing

Swamp Thing Vol. 2 #170 (September 1996): "Trial By Fire, Part 5: Apocalypse Now"
Swamp Thing Vol. 2 #171 (October 1996): "Trial By Fire: The End"
Vertigo Secret Files: Swamp Thing #1 (November 2000): "Look Away" [Flashback]
Swamp Thing Vol. 2 #171 (October 1996): "Trial By Fire: The End"
Green Lantern Vol. 3 #81 (December 1996): "Funeral For A Hero"
Swamp Thing Vol. 3 #2 (June 2000) "A Tree Falls In the Forest" [Flashback]
Swamp Thing Vol. 3 #10 (February 2001): ""Silk Cut" [Flashback]
Aquaman Vol. 5 #32 (May 1997): "Sea of Green"
Aquaman Vol. 5 #33 (June 1997): "Vision Quest"
Spectre Vol. 3 #62 (February 1998): "Final Rites"
Swamp Thing Vol. 3 #1 (May 2000): "In Lieu of Flowers" [Flashback]
Vertigo Secret Files: Swamp Thing #1 (November 2000): "Lady Arcane" [Flashback]
V2K: Totems #1 (February 2000) "Totems"
Swamp Thing Vol. 3 #6 (October 2000): "Killing Time, Part Three: Destiny Manifest"
Swamp Thing Vol. 3 #17 (September 2001): "Red Harvest, Conclusion: Topiary"
Swamp Thing Vol. 3 #18 (October 2001): "Last of the Loose Ends"
Hellblazer #184 (July 2003): "Third Worlds Part One: The Wild Card"
Hellblazer #185 (August 2003): "Third Worlds Part Two: Ordeal"
Hellblazer #189 (December 2003): "Staring at the Wall, Part One"
Hellblazer #192: (March 2004): "Staring at the Wall, Part Four"
Hellblazer #193 (April 2004): "Staring at the Wall, Conclusion"
Swamp Thing Vol. 4 #2 (June 2004): "Bad Seed, Part Two" [Flashback]
Swamp Thing Vol. 4 #1 (May 2004): "Bad Seed, Part One"
Swamp Thing Vol. 4 #2 (June 2004): "Bad Seed, Part Two"
Swamp Thing Vol. 4 #3 (July 2004): "Bad Seed, Part Three"
Swamp Thing Vol. 4 #4 (August 2004): "Bad Seed, Part Four"
Swamp Thing Vol. 4 #5 (September 2004): "Bad Seed, Part Five"
Swamp Thing Vol. 4 #6 (October 2004): "Bad Seed, Conclusion"
Swamp Thing Vol. 4 #7 (November 2004): "Missing Links, Part One"
Swamp Thing Vol. 4 #8 (December 2004): "Missing Links, Conclusion"
Swamp Thing Vol. 4 #9 (January 2005): "Love in Vain, Chapter One"
Swamp Thing Vol. 4 #10 (February 2005): "Love in Vain, Chapter Two"
Swamp Thing Vol. 4 #11 (March 2005): "Love in Vain, Chapter Three"
Swamp Thing Vol. 4 #12 (April 2005): "Love in Vain, Chapter Four"
Swamp Thing Vol. 4 #13 (May 2005): "Measure of Faith, Chapter One"
Swamp Thing Vol. 4 #14 (June 2005): "Measure of Faith, Chapter Two"
Swamp Thing Vol. 4 #15 (July 2005): "Healing the Breach, Chapter I-The Emotional Hostage"
Swamp Thing Vol. 4 #16 (August 2005): "Healing the Breach, Chapter II-Where The Rushing Waters Go"
Swamp Thing Vol. 4 #17 (September 2005): "Healing the Breach, Chapter III-While Sinking"
Swamp Thing Vol. 4 #18 (October 2005): "Healing the Breach, Chapter IV-Seeding Madness"
Swamp Thing Vol. 4 #19 (November 2005): "The Holland Mind"
Swamp Thing Vol. 4 #20 (December 2005): "Little Runaway"
Hellblazer #215 (February 2006): "R.S.V.P., Part 2"
Swamp Thing Vol. 4 #21 (January 2006): "The Bleeding Raconteur, Part 1-StoryTeller Down"
Swamp Thing Vol. 4 #22 (February 2006): "The Bleeding Raconteur, Part 2—A Hair-Trigger Heart"
Swamp Thing Vol. 4 #23 (March 2006): "The Bleeding Raconteur, Part 3—Letting Go"
Swamp Thing Vol. 4 #24 (April 2006): "The Bleeding Raconteur, Part 4—Emendation"
Swamp Thing Vol. 4 #25 (May 2006): "Meanwhile, In Houma..."
Swamp Thing Vol. 4 #26 (June 2006): "Burying the Bones"
Infinite Crisis #6 (May 2006): "Touchdown"
Infinite Crisis #7 (June 2006): "Finale"
Swamp Thing Vol. 4 #27 (July 2006): "The Prison Tree, Chapter I"
Swamp Thing Vol. 4 #28 (August 2006): "The Prison Tree, Chapter II"
Swamp Thing Vol. 4 #29 (September 2006): "The Prison Tree, Conclusion"
House of Mystery: A Special Sneak Peak (June 2008)

Where is #81, and why isn't it before Black Orchid? #81 is an Invasion! tite in, and Black Orchid was involved in Invasion!.

The answer to the first part is easy. Swamp Thing wasn't in issue #81 (except for a dream sequence and should be removed from the index).

As for the second part I'm afraid you are right. Black Orchid (the original) was shown in Invasion #2 and since Swamp Thing #81 was an Invasion First Strike tie-in, Invasion should take place after #81. Unfortunately that means Black Orchid #3 has to be moved all the way to after Swamp Thing #90 as he didn't return to his own time until then. The other alternative is to treat her appearance in Invasion as a mistake, but since she appeared in Suicide Squad #22 just prior to Invasion that doesn't leave enough room for all of the Black Orchid series to hae taken place. I haven't checked if there's something that speaks against moving it to after Swamp Thing #90 though.

From the information I have, between Swamp Thing #90 and #91 is the Elemental War in the pages of Firestorm 90-93, if that's any help.

That what we have as well. What I meant was if any of the other things in the Black Orchid series spoke against it being placed there. For Swamp Thing I don't think it would be a problem.