The Red Weed and Other Martian Vegetation

"Apparently the vegetable kingdom in Mars, instead of having green for a
dominant colour, is of a vivid blood-red tint. At any rate, the seeds which the
Martians (intentionally or accidentally) brought with them gave rise in all
cases to red-coloured growths. Only that known popularly as the red weed,
however, gained any footing in competition with terrestrial forms. The red
creeper was quite a transitory growth, and few people have seen it growing. For
a time, however, the red weed grew with astonishing vigour and luxuriance...
especially wherever there was a stream of water."

The strange plants which sprung up across the land shortly after the arrival of
the Martians have been universally dubbed "Red Weed", regardless of actual
characteristics. These include the Red Creeper, which swarmed up buildings and
trees like a scarlet ivy, strangling plants with its crimson fronds, and the
Red Sponge, a kind of algal growth which was briefly seen floating down the
Thames. The most common form, and the most long-lived of the Martian plants,
was the variety now known as the Red Weed, a bulbous growth similar in form to
certain species of cactus or succulent desert vegetation. In structure the
plant was arranged as a stocky stem not dissimilar in structure to the stems of
tropical plants, perhaps an inch thick and easily snapped, from which grew a
number of fleshy lobes, generally the size of a man's hand. The Weed has thick,
rubbery skin, reducing the loss of moisture by evaporation and protecting it
from the intense cold of the Martian climate.

The individual cells of the plant, when examined under a microscope, are very
large compared with the cells of terrestrial plants, and are mostly filled with
thin, watery sap. The fact that the Red Weed was only found in close proximity
to bodies of water, or where the ground was naturally damp, indicates that they
require a large amount of moisture to survive - if deprived of that moisture,
the large cells will become flaccid, and the whole plant will wilt and die. 

The Red Weed grows voraciously, having been reported to grow as much as three
feet in one day. It spreads with alarming rapidity, and within a week of the
Martians first landing the weed had spread all along the Thames Valley. The
Weed grows in spurts, dawn of each day marking the growth period. As soon as
the sun's rays touch the plants, they writhe and grow, rustling and waving of
their own accord, and seed pods burst with loud reports, scattering the seeds
beyond the mass of weed so that the plant can slowly encroach upon unclaimed
land. The seeds start growing almost immediately, especially if there is an
abundance of moisture about, for example in rivers or after a rainstorm.

It has been discovered that the Red Weed is in fact quite edible, if somewhat
unpalatable. It has a watery, metallic flavour, which some claim reminds them
of medicinal iron tonic. Other than a certain amount of iron and other trace
minerals leached from the soil (depending upon where the weed grew), is has
little nutritional value, being composed mostly of water and cellulose. Still,
some survivors of the Invasion tell stories of how they were forced to live on
Red Weed during the Martian occupation, even brewing it up into a watery soup,
and it seems to have done them little harm.

From the plant's characteristics, is has been theorised that this species was
actually designed by the Martians to reduce the amount of water lost by
evaporation from their canals, and tracts of irrigated land can be seen from
Earth using a reasonably powerful telescope. It can be deduced that the
seasonal changes on the face of Mars noticed by Mr. Lowell at his observatory
in Arizona are indeed the effects of changing seasons on the Martian
vegetation. It is quite likely that the Red Weed and its related varieties are
planted along the banks of the canals, and it is these vast swathes of
vegetation that rendered the canals visible from Earth, as the canals
themselves would be far too narrow to see even with the finest telescope. 
