Cirsium in North Dakota

Abstract

I. CIRSIUM NEBRASKENSE. Carduus nebraskensis B3ritton, in Britton and Brown, Ill. Flora III., p. 487 (1898). Cirsium nebraskense Lunell. This species is found occasionally mixed with the following variety in meadows and pastures, and in its natural, undisturbed growth it reaches the same size as the latter. Like the latter it has the pappus-bristles of the outer flowers barbellate, and of the inner plumose. Its involucres are glutinous. It can be produced pathologically from the following by cutting or otherwise injuring the stem, alnd the parts growing out afterwards above the injury have entire or slightly toothed leaves. 2. Cirsium nebraskense var. discissum var. nov. Folia lanceolato-oblonga vel lanceolata, lobis dentatis triangularibus oblongis vel lanceolatis profundis magis minusve spinosis vestita. Involucra et seti papposi speciei consimiles. Leaves lanceolate-oblong or lanceolate with dentate triangular, oblong or lanceolate, deep lobes, more or less prickly. Involucres and pappus-bristles as in the species. This is the most common thistle in the state, and has been identified under various different names. The state institutions have agreed abotut Cnicus undulatus as the correct name, as has been repeatedly shown in their biil1etins of earlier and later dates. An exalted eastern institution of learning has called it Cnicus altissimnus filipendulus (in comnion with the species), and this identification stimulated me to spend many houirs on physical exercise of changing the original position of bushels of dirt, for the futile purpose of unearthing its tubers, which were nothing but imaginary quantities as far as this thistle is concerned. I have myself been used to recognize it as Cardtms Flodmnannii Rydb., which suggestion was accepted by Dr. F. Petrak when the North Dakota plant of my collection was incorporated with his Cirsiotheca unitersa II., no. I9 (i9I i) as Cirsium Flodmannbi Petrak. But Dr. Rydberg's species has its pappus-bristles plumose (vide Memoirs of the New York Botanical Garden I, p. 451 (1900),