Actually, I was recalling that derivation from an article by Asimov.
Only if you want to limit yourself to the most commonly used adjective.
From dictionary.com
Note the spelling.
Venerean was sometimes used as a fancy word for Venusian, but the similarity to venereal killed it as a popular word.
DocCathode, The OP was about what astronomers thought, and it’s always easier to answer what the scientific community thinks than what the public thinks. Scientists have this extremely useful tendency to write down their consensus opinion at any moment.
The educated public, of course, would read popular science books like Clarke’s, or those by Willy Ley, or other science writers. Or at least the speculations of science fiction writers, who were rapidly moving away from the Burroughs Mars and Venus by the 1950s.
The ignorant public would think all kinds of things, the more fun the better, and would be fed in their ignorance by popular media, then as now.
If Clarke’s essay was reflecting what astronomers thought, then the OP is correct in the supposition that they thought Mars had plant life.
I grew up in the 1950s, and read a lot about astronomy at the time. Of course, it was popular science rather than the technical literature, but it wasn’t just science fiction. As I recall, it was generally thought at the time that Mars did have vegetation.
We Tellurians have many words with multiple, correct spellings. 
Yeah, that’s what I said. I’m not sure what you’re arguing.
Maybe it’s the green part. There’s a huge difference between inferring the presence of plant life from a seasonal darkening of areas and seeing green areas on a photograph. If you stop to think about it, you have no reason to suppose that Martian plants would be green the way earth plants commonly are. Greenness is from the presence of chlorophyll, which is used in photosynthesis. A different process would almost certainly have to be involved on Mars. Some chemical might be involved in using the oxygen from the soil but the likelihood of its also being green would be very small.
But I don’t think that any scientist thought there were green plants on Mars. Something small form and dark, maybe, but that’s not quite the same thing.
Squink, so other people besides you can’t spell. This is the Internet, after all. 
Thanks to all the disagreeing astronomers, I can’t tell you how many planets or moons around planets there are. Come to a consenses, and define planet and moon. Do we have a new planet or did we lose a planet or it’s still in limbo. I don’t know what the poor teacher should tell the class. Astronomy has turned everything I knew on end in the last decade, and not righted the apple cart.
There are plans to come up with a definition for a planet at the IAU meeting this month, and announce it in September.
But rest assured, astronomers will still have things to fight over and confuse everybody about after that 
Definition of ‘Planet’ Expected in September
The IAU will publish beginning of september 2006 the definition of a “Planet”.
Exapno, you’re quibbling about the green – to most writers “darjk” and “green” were synonymous. Through ground-based telescopes, dark green and black aren’t clearly distinguishable. The astronomy books I had as a kid (dating from the 1950s and 1960s) showed the anomalous regions of Mars as dark green, and hinted at vegetation.
Heck, Arthur C. Clarke himself wrote a science fiction novel about life on Mars in the 1950s, The Sands of Mars. He always tried to keep within the bounds of knowledge so he was still speculating that there could be vegetation and animal life on Mars (and on the Moon as well – read Earthlight for his description of possible lunar plants). Heinlein wrote Red Planet about a Mars with plants, canals, and intelligent life, then followed it up with Stranger in a Strange Land in the 1960s, and in his speculative essay “Where to?” it’s clear that he held out hope for life on Mars from 1951 to 1965 (when it was reprinted in The Worlds of Robert Heinlein) to even 1981 (reprinted in Expanded Universe). Some ideas (or hopes) die hard. Heck, Larry Niven was putting intelligent Martians there in the 1960s and 1970s in his Known Space series.
And, of course, the second attempt at invasion, at the end of October 1938, failed because the Martians foolishly landed in New Jersey. Many people think that New Jersey’s rather ripe reputation derives from a lack of commitment to environmental concerns. It’s actually one of the most carefully protected secrets in Garden State government’s innermost chambers that it’s a defense in depth against the Martians!
Great! I hope they make up their minds better than the UN council.
IIRC there was a National Geographic article as late as 1969 or 1970 that still suggested the “green” areas might be covered with plants of some kind. In retrospect, I can’t believe thatthe magazine would have printed that after the first Mariners had shown Mars to resemble the Moon more than any eartly desert. To help identify the article for anyone else who may remember it, there was a picture of a young Carl Sagan, who might also have written or contributed to the article.
Cal, if Clarke meant green he would have said green, not dark.
Sure there was a slow death of what was a fertile, pardon the pun, field for stories. Even the hard sf boys were writing to compete for the reader’s beer money, in the infamous phrase, and their science was only as good as it had to be when it didn’t get in the way of the storytelling.
And Roger Zelazny finished off the life on Mars and oceans on Venus stories with “A Rose for Ecclesiastes” in 1963 and “The Doors of His Face, The Lamps of His Mouth” in 1965, respectively. After that, no self-respecting writer took the genre seriously.
You can see a similar trend today, in which a few sf writers do serious extrapolations of all hard science trends into the future and come up with unintelligibly dense treatises about non-human humans while mainstream writers are mining the tropes in ways the public can understand them and getting reviewed in the Times Book Review. You can write hard science or for the public but never both at once.
I got the impression that Zelazny was consciously ignoring science for the sake of story- in the case of Rose, a damn fine story.
I don’t think we should infer that because a science fiction writer placed intelligent life on Mars means he really thought it possible. Certainly Ray Bradbury never pretended so. Mars is just a stage set for science fiction writing.
My point is that others were still depicting those dark regions aas dark green until the early 1960s. And Clarke, in his fictional Sands of Mars, had it green, too. I’ve got plenty of illustrations of Mars fro the 1950s and early 1960s with obviously dark green features.
As for no SF writer putting life on Mars after Zelazny, you have to take into account Larry Niven, who had intelligent Nartians in his stories well after that. You could argue that his novel Ringworld’s Children supports the idea, but it’s kinda worked intyo the Ringworld background now, andhe can’t abandon it.
Walloon, you’re right that just because an SF writer writes about an idea doesn’t prove that he believes it. But Heinlein was quite clear in his updates of “Where to?” in both 1965 and 1980 that he still did think they’d find life on Mars.
I suspect that in some cases (like Clarke’s Mars and Lunar life) that they know thety’re pushing the envelope of probability, but they like the idea of pushing as far as they can and still be within defensible science, since Nasture has a way of being surprising. Bradbury isn’t hard-core SF, and I don’t expect it of him. But Heinlein, Niven, and Clarke are hard-core SF, and it’s not like them to write something completely and blatantly outside the bounds (aside from the accepted heresies like FTL, time travel, and the like).
Interestingly, Clarke is still on the Life on Mars bandwagon. He’s claimed these images from the Mars Global Surveyor probe show Martian “Banyan Trees”. Here’s an interview from 2001 where he talks about them.
Doh! Fixed link here.
Those trees would have to have some mighty deep roots! I mean, there’s still no sign of free water on the Martian surface, is there?