Crocus
3 of the 7 encyclopedias on this shelf carry an entry for Crocus. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
a genus of iridaceæ. The perianth, which is single, is colored. The tube is long and the limb cut into six equal segments. The root a corm, the leaves grassy. The appropriate habitat of the crocuses is in the S. and E. of Europe and in Asia Minor. Some are vernal, others flower in autumn. luteus is the common or large yellow crocus. It was carried from Turkey to various parts of Europe in A. D. 1629. C. mæsiacus, imported from Greece in the same year, may not be distinct; nor may C. aureus, the small yellow crocus, also from Greece. C. lagenæflorous, another Greek species, has redyellow, paleyellow, and more typical yellow varieties . C. vernus is the common purple or white spring crocus C. sativus is an autumnal plant, brought from the East. It has long been cultivated for its long reddishorange drooping stigmas, which when dried become the saffron of the shops. According to Gussone C. odorus furnishes Sicilian saffron.
Aiton's Encyclopedia (1910)
a genus of plants belonging to the iris or flag family. The word is the Greek name for saffron. In fact the saffron of commerce is the pollen of the common crocus of the Mediterranean regions. About thirty species of the crocus are known to the American florist. Bulbs planted in the fall beneath the shelter of rich litter send up large flowers of many colors in early spring. The spendthrift crocus, bursting through the mold, Naked and shivering with his crop of gold. --O. W. Holmes.
American Watchmaker and Jeweler (1892)
Sesquioxide of iron used with oil for polishing brass and steel work. Crystals of sulphate of iron are subjected to a great heat, and then graded into polishing powders of various degrees of fineness. The more calcined part is of a bluish purple color, coarser and harder than the less calcined and is known as crocus. The less calcined and finer portion is of a scarlet color and is known as rouge.