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Volume 2294
By Rick Johnson

Terraformed Mars created by Darren Glidden using MOLA data 

Terraformed Mars from Kim Stanley Robinson's novel Blue Mars
Mars: Past & Future Vegetation


We all have read the papers of Captain John Carter who visited Mars in the late 19th century.  Most of us have sought to analyze the animals, history and technology of the Red Planet.  But the question remains, what kind of plants exist there?

Obviously, moss and a few trees but so many questions remain unanswered.  However, as vegetation is dependent upon many factors, one cannot simply state, as did John Carter,

"Coming, as they did, over the soft and soundless moss, which covers practically the entire surface of Mars with the exception of the frozen areas at the poles and the scattered cultivated districts."  [italics mine]
Instead we see clues here and there that give details to this statement.  Questions we would ask are: Where do these plants grow and why?  What kind of plants exist and why?  What is this moss and why does it grow everywhere? To these and more do I propose this paper.

But nothing exists alone.  Just as politics are determined by geography, so is animal life dependent upon the distribution of vegetation.  And that vegetation is dependent upon many factors.  These are just some.

Note that in places I have changed the case to Italics!  These are important so notice these.


I have a book called Extraterrestrials, a Field Guide for Earthlings by Terence Dickinson & Adolf Schaller.  Although this refers to SF as a genre, there is one chapter on Low-Gravity worlds that is relevant.  Heavy-g worlds won't have tall antelope-like beasts because they will break their legs with every step.  Low-g worlds are the opposite.  Why have massive animals and plants when the gravity allows for lighter ones?

The Gravity of Mars is 38% of that of Earth.  Slightly more than 1/3, but still acceptable.  Thus if you weigh 175# on Earth, you will weigh (175 x .38= ….) 66# on Mars.  A few bits of math here:

This makes you 2.6 times as strong on Mars as you would be on Earth.
The average human in good condition can do a standing long-jump equal to his height.   So if you are 6' tall, you can jump about 6' away.  On Mars you can jump 15'
The average person in good condition can jump up to almost ½ his height.  So if you are 6', you can leap to the top of a 3' table on Earth.  On Mars you can leap to the top of a 7' roof.
I have no idea of how John Carter could accomplish such fantastic leaps that he recorded.

Still, with only 38% of the gravity to fight, you don't NEED to be strong.

Elephants have such massively thick legs because they must support four tons of meat.  An elephant is one of two land animals that can neither run nor leap.  The tortoise is the other.  If an elephant steps off a simple street curb without warning, the force of that 6” drop will shatter his leg bone.

Now, as each leg must support a ton of weight, double the legs as in a zitidar or Green man's thoat, the elephant now must support only 1000# per leg.  Each leg supports ½ the previous weight so can be ¼ thinner.  It's the square-cube law. Trust me on this.  Or better yet, check it out yourself.

So now we have an elephant that has 8 legs, each one thinner by ¼ than before.  Now reduce the entire elephant's weight to Mars gravity!  He weighs a total of 3,000#.  Divide that by 8 and you get each leg supporting 380#.

The average horse weighs about 1500# so each leg of a horse only supports 375#.

Wow!  This means that a Zitidar the size of an elephant can have legs like a horse!  Animals on Mars do not need mass to support mass because the gravity is small enough to allow lightness in supports.

So think FRAGILE!  Think THIN!  John Carter said that were a 15’ tall Green Man to be transported to Earth, it would not be strong enough to support itself.  Tall and thin.

The same for plants.  An Oak Tree has a massively woody trunk to support the branches and leaves it grows.  Reduce gravity and the trunk vanishes!  Look at seaweed!  With no gravity to fight, they are thin, fragile and tall!  So plants on Mars would be similar to ferns or dry-land seaweeds. Giant ferns and giant bushes but actual trees would be rare.

When John Carter saw the first Thoats, gigantic beasts that are about elephant sized, he called them horses ONLY because he saw them being ridden.  His preconceptions controlled his images.   Had he seen a herd of wild thoats on the sea-bottom, he would have called them antelopes.

So, when John Carter sees a bush or fern growing from a single or multiple stem to a height over his head, he would call it a ‘tree’.

But these have no strength because they don't need strength.  You notice that John Carter never seems to climb ‘trees’ even for safety.  He cannot for they would snap under even his reduced weight.

38% gravity means that you get fragile looking plants that would fall over on Earth.


Mars is not a very large planet. Earth is massive enough for a number of things to happen.  First, when it was first forming and before it cooled, the heavier elements like Iron settled in the center.  Second, the mass of the Earth was great enough to keep the inside hot!  Hot enough to melt iron as the entire weight of the planet crushes and heats the planetary core!  So Earth has a semi-liquid core that doesn't turn as fast as the more solid surface.  It is this simple fact that causes that semi-molten iron core to generate the magnetic field that lets a magnetic compass work.

It also creates a magnetic field that is responsible for the Van Allen Belts that protect the Earth from UV and solar radiation.

Mars is too small for this to happen.  All the iron is locked into the surface.  And Mars is too light to keep any core liquid.  So Mars has no magnetic field.  A simple magnetic compass does not work.  And, with no magnetic field, there are no Van Allen Belts to protect the planet.  Mars suffers massive UV-bombardment.  Mars is 45% further from the Sun than is Earth so it receives much, much less UV than does Earth.  Double the distance and you receive ¼ the UV but the Van Allen Belts block most of our UV so the net result is that Mars gets more UV than do we on Earth.

So, think sunburn!  Martian plants and animals MUST have some way to filter out that UV.  Maybe the melanin in the skin of the Red Man does this.  But plants can become sunburned as easily as people. And UV = cancer so Martian life must have some method of being immune to cancer.  I don't know how this is so will ignore it but toss the thought out there.

Every planet in the Solar system suffered massive bombardment from space-based rocks.  Look at the Moon!  All those craters.  In some places the impact was so deep that it broke the crust and magma flowed to the surface before the Moon cooled.  On the Moon, these magma seas are the flat areas.

We even suffered this on Earth but eons of wind and mostly rain wore them down. But you still see them here and there.  Meteor Crater in Northern Arizona is the most famous.  But look at Canada.  Hudson Bay is a massive meteor impact crater.  James Bay is another impact crater that struck the Edge of the Hudson Crater.  Over the eons, these filled with water and erosion set in.  But they are still there.

Mars never had enough free water to wear down the craters.  All the Martian water was locked into the Five Oceans and rain was rare enough that the Craters remained intact.  In Chapter 3 of Princess of Mars, John Carter describes his advent on Mars:

"I found myself lying prone upon a bed of yellowish, moss-like vegetation which stretched around me in all directions for interminable miles. I seemed to be lying in a deep, circular basin, along the outer verge of which I could distinguish the irregularities of low hills."
Obviously he is describing an ancient Meteoric Impact Crater that he would later refer to as a ‘valley’.  In the time of John Carter, the ideas of Impact Craters was virtually unknown so by the time JC saw a map of Mars that revealed all the circular ‘valleys’, he would have already mentally translated ‘crater’ as ‘valley.

So Mars is covered with impact craters.  Some of these will capture airborne moisture in sufficient quantities that vegetation can thrive.  Look at the island of Oahu!  The winds blow in from the NorthEast and the volcanic crater that is the island blocks this wind.  The NE shore is a jungle.  What little water makes it over the ‘hills’ is barely enough to water the island.  Then there is the other side of the volcanic cone… the SW side of the island is a desert despite having the ocean right there.

When John Carter talks about the Valley of Helium and the Forest at the edge of the Valley, he is referring to a massive Meteor Impact Crater whose NW edge captures enough moisture to allow a few true trees to grow.


Mars is Desert!  But there are many kinds of deserts.
 *Antarctica is a desert because all the water is locked up in the ice.
 *The Sahara is a desert because it never rains there.
*Southern Arizona is a Desert because although it possesses two rainy seasons, the ground is so hard that the water flows off before it can soak into the ground.
*Baja California is a desert because, despite being surrounded by the Pacific Ocean and the Sea of Cortez, there is no way for that water to reach the land only a few feet above the ocean.
So although Mars is a desert, there are a number of kinds of deserts on Mars.  And if you look at the planet, you see clearly defined zones.

At the poles there is ice.  This is the Arctic Zone.  The Northern Ice cap is static.  It is always the same size so here is where they built the ice-melting and water pumping stations that feed the Waterways of Mars.

Nothing grows here.   Ice is not conducive to plant growth so you find only ice and snow.  And the Apt!

In the south, the Southern Ice cap varies.  It shrinks to almost nothing, then grows to a massive size.  The effort of building any stations here would be impossible.  You build one at the edge of the southern ice cap and in the Summer, the ice cap retreats.  In the Winter, your station is buried under the ice.  This is why all the Waterways come from the North!  Even Helium in the south depends on a Northern Waterway.

Nothing grows in the ice but this southern ice cap grows and shrinks.  As it grows, life retreats underground.  In the Summer when the ice cap shrinks, plants take advantage of the ice melt and the short growing season and moss and other plants explode while they can.  Almost overnight, a barren rock is covered with scarlet moss, followed by the other plants of Mars.  Then as the snow returns in the Winter, they die and are buried under the ice sheet, to await the Spring thaw.

The Northern Temperate region is a very narrow band that surrounds the Northern Ice cap.  It is here where the snow melt provides enough water for lush vegetation.  You may even find forests of real trees here.  Although cold to freezing at night, it is cool to warm during the day.

If it can grow on Mars, it will grow here in abundance and huge herds of thoat and zitidar feast upon this bounty where the moss is so thick, you can sink into it to your knees.    Also you will find Apts come down to hunt the northern edges of these herds as packs of banths and calots hunt the southern edges of the herds.

In the south, this zone is wider but moves.  In the winter, the Southern Temperate Zone reaches north by a dozen degrees.  But this same zone will shrink in the Summer, leaving a once lush savannah, now a barren desert.

Most of Mars is desert.  Hot during the day, cold at night.  Little water and most of that locked into the soil where it combines with the meteoric iron to give Mars his red color.  Mars is rusting away!  There is one known river here, the Iss but many impact craters that manage to capture enough moisture to support human habitation.  It is in this Arid Zone where moss prevails.  Thick in the dead seabeds, thin in the Lowlands and sparse in the High Deserts.  The herds of Thoat on the seabeds are not as large as up north but infinitely larger than those of the lowlands where a family-group of thoats is hunted by a solitary banth.


Throughout the entire series, the moss and grass are referred to as being red or reddish or occasionally yellowish-ochre.  I have a theory, but I do not hesitate to proclaim that this is simply an idea with no hard evidence at all.

On Earth, when life was forming, there was a war between red-algae and green-algae.  Green-algae won which is why all plants on earth are descended from green-algae and so are green.

IF the same thing happened on Mars, then red-algae won and this is why Martian vegetation is red.

My other theory is that the surface of Mars is littered with impact craters and as many, half or most meteors are stony-iron, as these meteorites struck the planet, many vaporized and thus the surface of Mars was filled with iron.  Mix iron with water and you get rust!  Mars is red because the surface is rusting away.  And so as the plants on Mars ingest the soils in which they grow, it is not impossible that the plants of Mars are red because they contain large amounts of iron.

As I said, these are simply ideas and are open to debate and refutation.  The one thing that is a fact is that most vegetation upon Mars is red in color.

When you look at the vegetation map, you see a series of colors:
*Bright Red indicates a well-watered forest.  Kamtol, Koal, Lost Souls, Dor and a very few others.  These are places where water flows naturally or there are hills to capture the wind-borne moisture in sufficient amounts to support such vegetation.  Think of the NE shore of Oahu.

*Red indicates a Dead Sea Bottom.   As the rains eroded the lands, topsoil washed into the seas to settle.  Fish died and sank to mix with this topsoil.  Fish poop fell also and as the seas dried, this mix became very rich soil.  Here the land is low enough for any remaining water to settle so with rich soil and the remains of the water in the soil, moss here grows rich and healthy.

*Orange is the Lowlands, or former shores and places of habitation.  Once fertile, eons of farming and erosion have washed away the topsoil, leaving the ground poor.  Moss that grows here lives, but isn't as lush as on the seabeds for there is little moisture in these areas.  Think of inland Hawaii.  Alive but not as lush as the NE coast.

*Next we see Light Brown which indicates High Desert.  Mostly rocks with little vegetation, this is where the NASA probes landed.  In the High Desert, what vegetation there is, is stunted by lack of water and by poor soil and is yellowish in color.  The winds that sweep Mars rob these High Desert Areas of both moisture and soil, thus, life here barely manages to exist.  Here is where the Green Hoards were driven by the Orovars.  Think the desert of SW Oahu.

*And finally is the Dark Brown of the Mountains.  Few are higher than 3,000 feet but the air thins here and there is little water so most are lifeless rock.  Even Duhor sits at the foot of the Artolian Hills even though these are the few that retain the snow that Duhor mines for their own use.  It is these snow-mines that allow Duhor to live without a Waterway.

*Exceptions are the Toonoolian Marsh which is the remains of a large bay, still filled with water that overflows into the River Iss.  Here are plants that demand lots of water for the moss and mantilla cannot survive in the swamps.

*Along the Iss you will find the occasional impact crater that filled with water to become an isolated lake or swamp or grasslands and here you will find the very rare lost city of apostates that turned away from the Pilgrimage.

*And finally is the Valley Dor, situated along the shore of the Sea of Korus, this is well watered.  These three ecosystems are so unique that they deserve a chapter or even a paper for themselves.

But the general rule here is that the Redder the vegetation, the healthier and more lush.  As the color faded to orange then yellow then brown, so does the health of the vegetation.  Anything that can survive on yellow-ochre moss is hardy and desperate indeed.


Have you ever wondered why movies like Princess of Mars are always shown as deserts?

Part of it is because you don't have all those pesky trees to film around, but mostly it is because in a barren rocky desert, you don't have to ask yourself what kind to vegetation would exist on an alien planet.  It simply makes the FX easier to do.


The first and most obvious form of plant life upon Mars is the Moss that grows almost everywhere.  As I quote again from John Carter's advent upon the Red Planet, A Princess of Mars chapter 3:

 "I found myself lying prone upon a bed of yellowish, moss-like vegetation which stretched around me in all directions for interminable miles. I seemed to be lying in a deep, circular basin, along the outer verge of which I could distinguish the irregularities of low hills.”  (italics mine)
I note that He initially refers to the plant as moss-LIKE!  Not true moss as we know on Earth but something that looks and feels like moss, but is different enough for even such a non-botanist as Captain Carter to notice.  He also refers to it as ‘yellowish’, not red, which implies that this was stunted from lack of water.  Probably the red-moss turns yellow in the High Desert where water is scarce and the soil poor. Still, that crater was wall-to-wall moss which implies soil that is not as good as the lowlands but still better than the High Desert.  We don't know exactly where that was other than the Green Man choose to place their incubators far from their own territories, which tells me that the Tharks would have moved into the High Desert to find a suitable and isolated crater where they could place their incubator in relative safety.  One where the walls of the crater prevents the topsoil from being blown or eroded away, though without adequate moisture to attract thoats which would attract banth which would find the Tharkian eggs an easy meal.

Again, from that same book and chapter:

"Coming, as they did, over the soft and soundless moss, which covers practically the entire surface of Mars with the exception of the frozen areas at the poles and the scattered cultivated districts.”

This implies that the Moss (Captain Carter initially describes it as “moss-like” then once the point was made, refers to it as “moss” for brevity) cannot tolerate water.  Like the saguaro cactus of Arizona, John Carter would have seen many of these in the Superstition Mountains where he and Powell searched for gold, yet none on the Salt River, for the Saguaro can grow only in dry ground, the Moss is an arid plant and requires some moisture, but true water drowns it.  You never see references to moss in the Toonol Marshes and rarely in the forests of Koal, Manator or Invak.  In fact, when John Carter describes the Valley Dor in Gods of Mars, an area well watered by the Lost Sea of Korus, he describes grass, not moss.

In Chapter 12:

"While the court was entirely overgrown with the yellow, moss-like vegetation which blankets practically the entire surface of Mars,"
Again and again we see the same reference.  The Moss grows everywhere save areas of water or snow.

In chapter 15:

"We traversed a trackless waste of moss which, bending to the pressure of broad tire or padded foot, rose up again behind us, leaving no sign that we had passed.

“Our animals had been two days without drink, nor had they had water for nearly two months, not since shortly after leaving Thark; but, as Tars Tarkas explained to me, they require but little and can live almost indefinitely upon the moss which covers Barsoom, and which, he told me, holds in its tiny stems sufficient moisture to meet the limited demands of the animals.”

And in Thuvia, Maid of Mars Chapter 6:
"His giant thoat was far from jaded, yet it would be well, thought Thar Ban, to permit him to graze upon the ochre moss which grows to greater height within the protected courtyards of deserted cities, where the soil is richer than on the sea-bottoms, and the plants partly shaded from the sun during the cloudless Martian day."
So what do we know about the Moss of Mars?
*First, it is moss-like, not true moss.
*Second, it requires some moisture but actual water prevents its growth.
*Third, it contains moisture like a succulent. Enough to easily support a large thoat.
*Fourth, it is extremely resilient and durable.  Not even large tires damage it for long.
*Fifth, given rich soil and some shade, it grows well and thick.
*Finally, under ideal conditions it grows red and thick, changing to orange then yellowish as the land dries and the soil impoverishes.
Where the moss fails to grow, it is replaced with grass.  We see in Gods of Mars when John Carter returns:
"I lay upon a close-cropped sward of red grasslike vegetation,"
"The vegetation was similar to that which covers the lawns of the Red Martians of the great waterways,"
In Warlord of Mars he describes in the Koal Forest:
"Slender purple grasses topped with red and yellow fern-like fronds grew rankly all about us to the height of several feet above my head."
Though later these fronds are referred to as star-like flowers.

In Llana of Gathol, John Carter describes the Valley of Kamtol, a great rift in the dead seabottom of Throxus:

"From our dizzy footing on that precarious trail we had an excellent view of the valley below. It was level and well watered and the monotony of the scarlet grass which grows on Mars where there is water, was broken by forests, the whole making an amazing sight for one familiar with this dying planet."  (italics mine)
What this tells us is that in the wetter areas such as forests, moss cannot grow, so is replaced by a grass-like vegetation.  This grass is grown as a lawn where one can afford to water it.  And at times, many of these grass-leaves have a flower.  The series is specific in that the flower grows on the end of each grass-leaf!  We will cover this later.

Thus you will no longer find grass anywhere save the forests and irrigated farmlands and lawns.  It simply cannot survive even on the Seabeds or craters where even the moss grows thick.

Flowers are described but not as we would know them.  Note that moss is described as ‘moss-LIKE’ and grass as ‘grass-LIKE’.  So flowers would be the same… flower-like!  I believe I have a reason for this.

In chapter ten of Princess, we read:
"Numerous brilliantly colored and strangely formed wild flowers dotted the ravines”

In Gods, in the Valley Dor:

"I lay upon a close-cropped sward of red grasslike vegetation, and about me stretched a grove of strange and beautiful trees, covered with huge and gorgeous blossoms and filled with brilliant, voiceless birds. I call them birds since they were winged, but mortal eye ne'er rested on such odd, unearthly shapes."

"And in the same way was the foliage as gay and variegated as the stems, while the blooms that clustered thick upon them may not be described in any earthly tongue, and indeed might challenge the language of the gods."

And a clue in Gods:
"An hour later found us in the time-rounded gullies of the hills, amid the beautiful flowering plants that abound in the arid waste places of Barsoom." (italics mine)
And in Warlord, chapter five:
"Myriad creepers hung festooned in graceful loops from tree to tree, and among them were several varieties of the Martian "man-flower," whose blooms have eyes and hands with which to see and seize the insects which form their diet."
In Thuvia Chapter one:
"Upon a massive bench of polished ersite beneath the gorgeous blooms of a giant pimalia a woman sat."
And later in chapter six:
"But here in the hills, where loose rock occasionally strewed the way; where black loam and wild flowers partially replaced the sombre monotony of the waste places of the lowlands, Carthoris hoped to find some sign that would lead him in the right direction."  (italics mine)
In Fighting Man of Mars, we read:
"Thuria and Cluros were racing through the heavens casting their soft light upon the garden of Tor Hatan, empurpling the vivid, scarlet sward and lending strange hues to the gorgeous blooms of pimalia and sorapus,"
Synthetic Men of Mars describes this interesting note:
"Gay plumed voiceless birds watched us from the branches of skeel and sorapus trees, as silent as the beautiful insects which hovered around the gorgeous blooms of the pimalia and gloresta which grew in profusion in every depression of the hills that held Barroom's scant moisture longest."
Note that flowers, save in cultivated areas where they are deliberately grown, seem to grow in poor areas, in ravines where they are protected from the sun and find adequate moisture.  Although found on trees, they are also seen as ‘wildflowers’.  Why?

On Earth, certain plants that grow in poor soil must supplement their diet with insects.  The Venus Flytrap and Pitcher Plant come to mind.  I believe that on Mars, flowers are NOT for reproduction as on Earth, but as a means to capture food.  The Man-Flower being the most commonly described but the Calot-Tree is another example.

What we have is a dying world where the soil is poor and even the plants seek any means to survive.  The Man-flower is specifically described as being carnivorous but I would propose that many other plants produce flowers to attract insects and small animals to consume.  The Pimalia, Sorapus and others are encouraged in the cities as insect control.  The Calot-tree is not encouraged as this is large enough to eat a person so does not need blossoms to attract victims upon which to predate.

Although the Calot-Tree is a sessile predator found in the desert and in the forests,

"The repulsive calot tree was, too, much in evidence. It is a carnivorous plant of about the bigness of a large sage-brush such as dots our western plains. Each branch ends in a set of strong jaws, which have been known to drag down and devour large and formidable beasts of prey."
…no plant is as active a predator as is the Plant Man!

The Plant Men of the Valley Dor have uprooted themselves and not only graze upon the Martian grass, they are a highly mobile and effective predatory plant:

"A race inhabiting the Valley Dor. They are ten or twelve feet in height when standing erect; their arms are very short and fashioned after the manner of an elephant's trunk, being sinuous; the body is hairless and ghoulish blue except for a broad band of white which encircles the protruding, single eye, the pupil, iris and ball of which are dead white. The nose is a ragged, inflamed, circular hole in the centre of the blank face, resembling a fresh bullet wound which has not yet commenced to bleed. There is no mouth in the head. With the exception of the face, the head is covered by a tangled mass of jet-black hair some eight or ten inches in length. Each hair is about the thickness of a large angleworm. The body, legs and feet are of human shape but of monstrous proportions, the feet being fully three feet long and very flat and broad. The method of feeding consists in running their odd hands over the surface of the turf, cropping off the tender vegetation with razor-like talons and sucking it up from two mouths, which lie one in the palm of each hand. They are equipped with a massive tail about six feet long, quite round where it joins the body, but tapering to a flat, thin blade toward the end, which trails at right angles to the ground."
Further, John Carter has observed these same ‘arms’ as being vampiric in that they fasten to animals and suck blood from the bodies of their victims.

Thus flowers on Mars are the predatory organs of certain plants.

Trees are rare upon Mars.  You never see one in the deserts or Seabeds.  Instead, they exist only in the forests and cultivated in the cities.  As the moss is moss-like and the grass is grass-like, I would venture that trees are tree-like.

In a low-gravity world like Mars, the woody trunk of a tree is unnecessary so most trees are probably overly large ferns or other plants that simply are able to grow large in the zero-point-three-eight gravity.

There are a few exceptions.  Whenever a tree is described, it is in well-watered areas such as the forests and swamp.  As Mars dried up, the tree was not able to survive and simply died out.  And even here, only a few trees are described.

In the Valley Dor, where logging has never existed, trees or tree-like plants managed to continue to grow for thousands of years thus reaching sizes and heights impossible on Earth.  I recall the younger sister of a friend who began to fertilize and water a simple weed.  I don't recall why but by the time they moved a few years later, that weed was as large and strong as a small tree!  I can see the same happening on Mars.

Wood is prized in every civilization, more so by desert cultures.  Renewable, if properly cultivated, wood has many uses.

In Princess John Carter describes that wood was used in window casings and doors, and STILL as strong today as it was when it was set a hundred thousand years ago.
"There seemed something menacing in their attitude toward my beast, and I hesitated to leave until I had learned the outcome. It was well I did so, for the warrior drew an evil looking pistol from its holster and was on the point of putting an end to the creature when I sprang forward and struck up his arm. The bullet striking the wooden casing of the window exploded, blowing a hole completely through the wood and masonry”

And in rifle stocks:

"These rifles were of a white metal stocked with wood, which I learned later was a very light and intensely hard growth much prized on Mars, and entirely unknown to us denizens of Earth"
But there seems to be another, lighter wood used in aircraft.  After the Tharks captures a large aircraft of Helium, they burn her thus:
"This operation concluded, they hastily clambered over her sides, sliding down the guy ropes to the ground. The last warrior to leave the deck turned and threw something back upon the vessel, waiting an instant to note the outcome of his act. As a faint spurt of flame rose from the point where the missile struck he swung over the side and was quickly upon the ground. Scarcely had he alighted than the guy ropes were simultaneous released, and the great warship, lightened by the removal of the loot, soared majestically into the air, her decks and upper works a mass of roaring flames.
"Slowly she drifted to the southeast, rising higher and higher as the flames ate away her wooden parts and diminished the weight upon her. Ascending to the roof of the building I watched her for hours, until finally she was lost in the dim vistas of the distance.
This implies that some form of lumber is light enough and strong enough to be preferable to aluminum in aircraft.

The trees specifically mentioned are:
A drought-resistant hardwood bearing delicious nuts.  It is made into ladders and doors and is said that Martian civilization was built upon the Skeel.
A kind of tree that bears “a citrus-like fruit with a thin red rind. The pulp of this fruit, called somp, is not unlike grapefruit, though much sweeter. It is considered a great delicacy among Barsoomians.
A Martian hardwood bearing a large delicious nut. The wood is made into furniture and occasionally structural members for houses.
 A tree that bears a fruit that is high in nutrition but is almost tasteless and must be cooked and highly spiced before it is considered fit for consumption.  Usa is a staple for military rations and much eaten by the poor who cannot afford much else.  It is referred to as ‘the fighting potato’.

There are also roots and tubers and berries mentioned but not named.

Although there are very rare comments of stunted trees or shrubs in the desert, generally, if it is a tree, it grows near water.  Almost always in a forest or swamp.  In the Valley Dor, there are trees with trunks a hundred feet in diameter and a height of a thousand feet (impossible if fighting the gravity of Earth)  which speaks of a long life and a lack of logging.

The Red Men cultivate trees along the waterways and in their cities both for food and decoration.  In the Arizona Desert, when I am looking for water, I gaze upon the distance seeking a ribbon of green which indicates trees, for here, trees grow only where planted and watered or along a riverbed.  On Mars, a ribbon of trees indicates a waterway and civilization.  Even the trees grown in a garden are harvested of their fruit and nuts for food.

Are these really trees?

The trunks are described as having no bark and are of various colors, as if highly polished.  So are these barkless plants true trees?

I believe they may be, though they are rare and probably poached for their lumber.  Yet, in the light gravity of Mars, I would argue that they are rarely as strong as oak simply because they do not need such strength.  Most trees would be light and frail by Earthly standards and those few like Skeel, would be highly prized and cultivated as in the Forest of Helium which is little more than a tree-farm along the NW crater wall.  Wood would be used and reused, never burned or allowed to rot because it is so valuable.  Tarzan would find travel among the upper terrace to be impossible.

Those few nations that possess actual forests such has Koal ,Manator and Invak, not to mention Toonol and Phundahl, are noted for being very aggressive and protective of their resources.  Koal has but a single allay, Ptarth.  I imagine that Ptarth goes to great lengths to retain this alliance because of the valuable timber it receives from Koal.

I wonder if there are wood-seekers who haunt the dead cities to cannibalize the ruins for the ancient wood left behind?  Such a dangerous occupation would be profitable enough to encourage some to try.


The Mantiliala is the life-saver of Mars.  From descriptions we learn again and again of its abilities.

From Princess we see John Carter's first experience with the life-saving Mantilia:

"While I was allowing my fancy to run riot in wild conjecture on the possible explanation of the strange anomalies which I had so far met with on Mars, Sola returned bearing both food and drink. These she placed on the floor beside me, and seating herself a short ways off regarded me intently. The food consisted of about a pound of some solid substance of the consistency of cheese and almost tasteless, while the liquid was apparently milk from some animal. It was not unpleasant to the taste, though slightly acid, and I learned in a short time to prize it very highly. It came, as I later discovered, not from an animal, as there is only one mammal on Mars and that one very rare indeed, but from a large plant which grows practically without water, but seems to distill its plentiful supply of milk from the products of the soil, the moisture of the air, and the rays of the sun. A single plant of this species will give eight or ten quarts of milk per day."

"My only food consisted of vegetable milk from the plants which gave so bounteously of this priceless fluid."

It is obvious that the Green Man either has a limited dietary requirement, or, as John Carter could easily live on this, the mantilia milk is capable of supporting humans.

And in Fighting Man Gahn describes:

 "After I passed over Xanator I discovered a large grove of mantalia growing out  upon the dead sea bottom and I immediately descended to obtain some of the milk from these plants.

 "The mantalia grove was an unusually large one and as the plants grew to a height of from eight to twelve sofads, the grove offered excellent protection from observation. I had no difficulty in finding a landing place well within its confines. In order to prevent detection from above, I ran my plane in among the concealing foliage of two over-arching mantalias and then set about obtaining a supply of milk.

"A band of green warriors had also entered the grove to procure milk, and, as I was tapping the tree I had selected, They must have been in a portion of the grove very thickly overhung by foliage while I was approaching from above by making my landing; but be that as it may, they were ignorant of the presence of my flier and I determined to keep them in ignorance of it.

"I knew that the fierce animals of the barren hills and the great white apes of the ruined cities were equally fond of the milk of the mantalia and that we should be fortunate, indeed, if we escaped an encounter.

And in Llana:
"For five days we saw no living thing. We subsisted entirely upon the milk of the mantalia plant, which grows apparently without water, distilling its plentiful supply of milk from the products of the soil, the slight moisture in the air, and the rays of the sun. A single plant of this species will give eight or ten quarts of milk a day. They are scattered across the dead sea bottoms as though by a beneficent Providence, giving both food and drink to man and beast."
From these descriptions we can conclude that the Mantilia is another desert plant, incapable of growing in wet areas for no mentions of this plant are given in the forests or swamps.  Nor do the Red or Green Men seem to cultivate the plant.  It simply grows wild in groves in the desert, generally in ravines or other places where some moisture is collected.

The plant itself is poorly described but exists in small groves and can grow to eight or even twelve feet high with lush overhanging leaves, though solitary plants are known.  The trunk is tapped for milk. A single plant can produce up to four gallons of highly nutritious milk a day, every day.

My own personal thoughts are that the mantilia resembles a large pineapple.  The leaves are probably rolled up and pulled in during the night to protect the plant then pushed out to open and turn to the sun during the day.  Tapping the plant would be easy, remove a scale and cut the inner flesh to cause a wound similar to that made in the Earthly Maple Tree.   I suspect that the solitary plants are smaller than those in groves which implies a single plant establishing itself, then sending out sub-surface roots that find a nice place which causes that root to sprout a 'daughter' plant.  Thus a grove would consist of the original matriarch plant which would be the largest, surrounded by her daughter plats and their daughter plants.

My main questions are:

1)  why don't the Green Man cultivate it?  Or is this another aspect of their ‘steal but don't produce’ philosophy?
2)  why don't the Red Men plant mantilia groves along trade routes?  Or if they do, does this signal the Green Men to ‘wait for a caravan’ to raid?
Regardless, the Mantilia is possibly Mars’ most perfect and useful plant.


In conclusion what can we say about the Vegetation of Mars?

Many things.

Vegetation is fragile due to the weak gravity.  Adapted to desert conditions.  And red!  The redder the color, the healthier the plant. The more yellowish, the more stunted the plant.

Even on Mars, vegetation grows where there is water.  Some plants are able to collect their water from the air that sweeps moisture from the Artolian Hills or possibly from breaking down the rust in the soil from eons of meteoric impacts.

Forests are rare, and trees are rarer.

Some plants are active predators, feeding mostly on insects and birds with a very few able to kill and eat even people.

Red Men cultivate useful plants, Green Men do not.  And those who possess any of the rare forests are aggressively protective of them.

This then is Mars.  A dying planet that has taken as many possible steps as it can to create a biota that manages to survive under the harshest of conditions.

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