More Free Sword and Science Fantasy Fiction - 'The Tree of Life ' by C. L. Moore From October 1936 issue of Weird Tales magazine

 

"A gripping tale of the planet Mars and the terrible monstrosity that called its victims to it from afar -- a tale of interplanetary space hero Northwest Smith."
Grab it right here. 

Most of you might be thinking that this blog entry is going to be where we dive deep into C.L. Moore's Northwest Smith  Mars.   If we look at 'The Tree of Life ' by C. L. Moore more closely there's a lot going on below the surface. 
 The actual danger comes to PC's who don't understand that the Lovecraftian Martian plant described in the story is actually a part of a much greater danger on Mars & elswhere. The plant life described in the story is similar to plant deities of Mars decribed by both Leigh Brackett & Clark Aston Smith. For CAS it was his story, 'The Dweller in the Gulf' is one where one of the ancient gods of Mars shows the upstart humans that not everything is gone on Mars. This entity might be similar to the occult cosmic entity found in Seedling of Mars and Vulthoom .  And as Boyd Pearson says in his article on Eldritch Darkness 'Cycles of Clark Ashton Smith'; "While The Vaults of Yoh-Vombis and The Dweller in the Gulf would of been equally effective stories had they been set on earth Seedling of Mars and Vulthoom utilised the 'alien invasion' motif popular in the pulps at the time However, theses did not contain your typical alien invasion scenarios Vulthoom was an alien 'god' (plant like) who came to mars when humans "were still the blood-brothers of the ape," and now wishes to move to Earth Vulthoom's plot is only temporarily foiled by being put back to sleep for a thousand years The plant thing in Seedling of Mars has better luck in that it does get to take over the earth" 

• Dweller in the Gulf, The (1933)
• Mnemoka (1955) Fragment
• Vaults of Yoh-Vombis, The (1931)
• Vulthoom (1935)

Seedling of Mars or The Planet Entity [plot by - E M Johnson] (1931)[An alternative background to the proceeding 4 stories] 

So what does any of this have to do with 'The Tree of Life ' by C. L. Moore? Everything there are very dangerous occult forces on Mars. Divine forces that work in various cycles of life & death just as some Earth life forms do according to the weather. And this plant entity encountered by Northwest Smith might simply be an extension of the former pantheon of Mars. And in point of fact these alien entities might be tied to Edgar Rice Burroughs Barsoomian plantmen. And in point in of fact these plantmen could be extensions of the Lovecraftian plant gods on Mars. 
But these types of entities are not just found on Mars. There are a literal ton of these plant monsters scattered throughout the Pulps. So it would be quite easy to add these monsters to your favorite OSR games! 
These plant gods & alien entities are the great survivors & are able to survive just about any disaster that might befall Mars and this includes a small nuclear war. 

The plantmen below is from Michael Whalen's Barsoom covers & used without permission.