INDUSTRIAL PROGRESS DURING THE YEAR 1873. cv 



the former being fitngi^ the latter algm or, in other words, 

 that every lichen is simply some fungus living upon some spe- 

 cies of alga. Van Tieghem has continued his study of the 

 embryo, showing how far its several members (cotyledons, 

 plumule, caudicle, and radicle) are independent of each other, 

 and capable separately of developing a comf)lete plant, and 

 also the nature of their connection with the albumen when 

 present. Professor Miiller, of Lipstadt, has published a com- 

 pend of the observations that have been made on the fertil- 

 ization of flowers by the agency of insects, with many orig- 

 inal facts and numerous illustrations, havinsj reference to the 

 peculiar structural modifications which exist in insects adapt- 

 ing them to this end, as well as in flowers. Dr. B. Sanderson, 

 of University College, London, in a paper before the British 

 Association, shows that in cases of irritability and motion in 

 plants, there exist electrical currents similar to those accom- 

 panying living animal muscle and nerve, and, so far as inves- 

 tigations have gone, governed by the same laws. 



In America, the Smithsonian Institution has published a 

 contribution by Dr. H. C. Wood, Jr., upon the Fresh-water 

 Algae of North America, supplementing the " Nereis Boreali- 

 Americana " of Harvey, and illustrated by excellent color- 

 ed lithographic plates. It describes all the known genera 

 and species, and a copious bibliography of previous authors 

 is added. In the Transactions of the St. Louis Academy, 

 Dr. George Engelmann has given his " Notes upon the Genus 

 Yucca," defining the species, and explaining the mode of 

 fertilization of the flower, which was previously unknown. 

 Dr. Asa Gray contributes to the Proceedings of the American 

 Academy characters of some new genera and species, and 

 notes upon Compositm^ having reference chiefly to the bear- 

 ing of Bentham's revision of the order upon the American flo- 

 ra, with a revision of the genus Bigeloma (or Linosyris), In 

 the same Proceedings has appeared a revision, by Sereno 

 Watson, of the large and somewhat difficult genera Xiqmius, 

 Potentilla, and (Enothera^ which have long needed re-elabo- 

 ration. A revision of the section Avicidaria of the genus 

 Polygonum^ and descriptions of a number of new plants from 

 Arizona or the adjacent region, by the same hand, have ap- 

 peared in the American Naturalist^ as also an anatomical 

 study of species oi Lemna by Professor T. D. Biscoe. Some 



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