H. BOTANY AND HORTICULTURE. 363 



titute of a shrub. Botanists have long been anxious to de- 

 termine the character of the Amsterdam forest, but the diffi- 

 culty of effecting a landing on the island has generally pre- 

 vented the collection of specimens. In the last part of the 

 journal of the Linnoean Society, Dr. Hooker announces that at 

 length he has received the desired specimens, these having 

 been collected by Commodore Goodenough, who states that 

 they represent the only species of tree growing on the isl- 

 and. Dr. Hooker identifies this with the Phylica arborea of 

 Thouars, a tree which, strangely enough, is found in the re- 

 mote island of Tristan d'Acunha. It is a problem for those 

 who study insular floras to suggest how the same plant can 

 have established itself on these two little specks of land sep- 

 arated from each other by about five thousand miles of ocean. 



LIST OF NORTH AMERICAN ALG^E. 



About twenty years ago the Smithsonian Institution pub- 

 lished an elaborate work, by Professor William H. Harvey, 

 of Dublin, upon the alga? or sea-weeds of North America, a 

 subject which has always been of popular interest, as nearly 

 all persons who visit the sea-shore are attracted by the beauty 

 of the floating: weeds, and are induced to make collections for 

 preservation. The publication of this work gave a renewed 

 impetus to the study, and at the present time there are many 

 collections in the United States, both public and private, the 

 determinations of all being based upon the work referred to. 

 Ko systematic effort, however, has been made to bring the 

 subject up to date, although Professor D. C. Eaton, of New 

 Haven, and Professor W. Gr. Farlow, of Cambridge, have been 

 ensealed in investigations looking toward a revision of the 

 group. Professor Farlow has, however, just published in 

 the proceedings of the American Academy of Arts and Sci- 

 ences of Boston a new list of the species, 430 in number, and 

 embracing about 54 additions. Proc. Amer.Acacl, 1875, 351. 



BOTANY OF THE LIBYAN DESERT. 



The Swedish botanist, Ascherson, has recently been explor- 

 ing the flora of the Libyan Desert, having been attached for 

 this purpose to the expedition of Rohlfs. Thirty-three spe- 

 cies, belonging to 14 different families, were met with in the 

 desert proper (e. g., at least an hour's journey from any of the 



