Credit to Tinman2
Extracted from, Prospectors Field Book And Guide, In the search for and the easy determination of ores and other useful minerals. published 1910
Indicative Plants
From early times it has been noted that the soil overlaying mineral veins is covered by special vegetation, an through such cannot be taken as an infallible indication of the existence of mineralization, it will be interesting to record the results of past observations so that they may serve as a guide to future observation.
The lead plant ( Amorphia canescerns ) is said by prospectors in Missouri Wisconsin and Illinois to be most abundant in soil overlaying the irregular deposits of galena in limestones.
It is a shrub one to three feet high covered to a hoary down. The light blue flowers are born on long spikes and the leave are arranged in close pairs on stems, being almost void of foot stalks. Gum trees or trees with dead tops also sumac and sassafras are observed in Missouri to be abundant where float galena is found in the clays.
A vein of iron ore near Siegen Germany can be traced for nearly two miles by birch trees growing on the outcrop, while the remainder of the country is covered with oak and beech
The beech tree is almost invariably prevalent on limestone and detached groups of these trees have led to discovery’s of unsuspected beds of limestone.
Phosphate miners in Estermadura, Spain find that the Convovlus altharoides a creeping plat with bell shaped flowers is a most reliable guide to the scattered and hidden deposits of phosphorite occurring along the contact of the Silurian shale’s of Devonian dolomite.
In Montana experienced miners look for the silver wherever the Eriogonum ovalifolium flourishes. This plant grows in low dense bushes, its small leaves coated with thick white down and its rose coloured flowers being born in clusters on long smooth stems.
The zinc violet Galmeiveilchen or Kelmesb (Viola calaminaria ) of Rhenish Prussa and contiguous parts of Belgium is there considered an almost infallible guide to calamine deposits, though in other districts it grows where no zinc has been found. In the zinc districts its flowers are coloured yellow and zinc has been extracted from the plant. The same flower has been noted at zinc mines in Utah.
In Alaska much of the gold bearing gravel is frozen necessitating thawing for its extraction. If a scrub willow is found growing on the surface, miners know that the ground is not frozen.
In the quicksilver bearing serpentine belt of California brush and trees are sparse and stunted. This rock is pale blue and green. In other parts of the serpentine area where the reddish colour of the soil indicates the presence of iron the under brush is fairly abundant.
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