﻿440 BOTANICAL GAZETTE [may 



Among the important foreign contributions is a paper by Wadsworth? 

 on the knapweed gall. This gall is most common on Centaur ea nigra L., a 

 very troublesome pasture weed, but also occurs C. scabiosa L„ C. montana L., 

 C. paniculata L., Cardims nutans I,.. ( . rrispus L., C. anthoides L., Cirwaw 

 lanceolatum L., Serratula tinctoria L., etc. The gall is caused by a dipterous 

 insect which was originally described in 1758. The adults emerge during a 

 period of about two weeks in June and deposit eggs on the young flower heads 

 early in July. The author gives synonomy, historical discussion, descrip- 

 tion, life history, and distribution of the insect. The effect of this falling is 

 to reduce the seed production to about 50 per cent. Of the seeds that are 

 produced only 60.5 per cent germinate. — Mel. T. Cook. 



Australian vegetation —In a country of vast extent and consequent widely 

 differing conditions it is difficult to gain any accurate concept of the most strik- 

 ing characters of the vegetation or of the principal affinities of the flora. Such 

 a characterization was prepared by Maiden 8 in connection with the recent visit 

 of the British Association to Australia. In reviewing the main natural divi- 

 sions of the country he calls attention to the "geocols," broad depressed areas 

 running east and west and separating wide plateaus, and to their possible 

 influence upon plant distribution. Interesting botanical statistics show among 

 other things that one family, the Leguminosae, is represented by 1275 species, 

 while the Myrtaceae, Proteaceae, and Compositae show over 500 species each. 

 Among remarkable prominent genera are Acacia with 412 species, and Eucalyp- 

 tus with 230 species. Incidentally it would seem that the largest specimens 

 of the latter of which authentic measurements exist are about 326 ft. in height 

 and 25 ft. 7 in. in circumference, 6 ft. from the ground, dimensions excelled by 

 the sequoias of America. 



Some attention is given to introduced plants, many of which are of vast 

 importance in the weed problems of the agricultural areas. The most remark- 

 able instance cited is that of the prickly pear, Opuntia inermis, introduced 

 from Rio de Janeiro in 1789 as food for the cochineal insect, which is now badly 



added annually by its natural increase. 



The flora is analyzed rather effectively and its various affinities demon- 

 strated. Finally, concise sketches are given of the flora and vegetational 

 types of the various individual states. It is impossible to summarize these 

 already condensed characterizations, but it may be of interest to note the 



7 Wads worth, J. T., Some observations on the life history and bionomics of the 

 knapweed gall fly Urophora soltitiallii "Linn. Annals Appl. Biol. 1:142-100. ioi4- 



8 Maiden, J. H., Australian vegetation. Federal handbook on Australia, 

 pp. 163-209. 1914. Issued in connection with the visit of the British Association for 



