which could only become intelligible on some theory of descent. The plan of life-story common to them all, involving two alternating generations, was demonstrated for Liverworts, Mosses, Ferns, Equiseta, Rhizocarps, Lycopodiaceae, and even Gymnosperms, with a completeness and certainty which must still surprise those who know the botanical literature of the author's time. The conclusions of Hofmeister remain in their broad outlines unshaken, but rather strengthened by later-acquired details. In the light of the theory of descent the common plan of life-history in plants apparently so diverse as those named acquires a special significance; but it is one of the remarkable features of this great work that the writer himself does not theorize--with an unerring insight he points out his comparisons and states his homologies, but does not indulge in explanatory surmises. It is the typical work of an heroic age of plant-morphology. From 1857 till 1862 Hofmeister wrote occasionally on physiological subjects, such as the ascent of sap, and curvatures of growing parts, but it was in morphology that he found his natural sphere. In 1861, in conjunction with other botanists, a plan was drawn up of a handbook of physiological botany, of which Hofmeister was to be editor. Though the original scheme was never completed, the editor himself contributed two notable parts, _Die Lehre von der Pflanzenzelle_ (1867) and _Allgemeine Morphologie der Gewachse_ (1868). The former gives an excellent summary of the structure and relations of the vegetable cell as then known, but it did not greatly modify current views. The latter was notable for its refutation of the spiral theory of leaf arrangement in plants, founded by C. F. Schimper and A. Braun. Hofmeister transferred the discussion from the mere study of mature form to the observation of the development of the parts, and substituted for the "spiral tendency" a mechanical theory based upon the observed fact that new branchings appear over the widest gaps which exist between next older branchings of like nature. With this important work Hofmeister's period of active production closed; he fell into ill-health, and retired from his academic duties some time before his death at Lindenau, near Leipzig, on the 12th of January 1877. (F. O. B.)