626 SUMMARY OF CURRENT RESEARCHES RELATING TO 



dance of narrow and partly closed flowers, and of those which, like 

 many species of Saxifraga and Veronica, are especially attractive to 

 Syrphidfe and other Diptera ; whereas, without a knowledge of the 

 relative distribution of the flower-frequenting insects, it would be a 

 hopeless riddle. 



The author has followed the excellent plan, adopted in his earlier 

 book, of compiling a systematic index to the insects observed, con- 

 necting with each species the flower it frequents and the degree of 

 their adaptive development. 



Nectaries of Flowers. — M. G. Bonnier, in papers published in 

 1879 and 1880,* claimed to have established that the colour of the 

 corolla, the perfume, &c., are not connected with the formation of nectar, 

 and do not act, therefore, to attract insects and efiect cross-fertilization. 

 Dr. H. Miiller has published f a strong criticism of M. Bonnier's 

 views, in which he contends that the proofs supjiosed to be given 

 are nothing but " an uninterrupted chain of grossly illogical affirma- 

 tions," and asserts that the author has "endeavoured with the weapons 

 of a child to overthrow one of the broadest and best founded of 

 theories." 



Extra-floral Nectaries. J — V. A. Poulsen describes the extra- 

 floral nectaries in the following plants : — 



1. Batatas glaherrima. — In the cortical tissue of the flower-stalk 

 immediately below the sepals ; they are hollow cavities clothed with 

 short, crowded, secreting glandular hairs, and opening by a narrow 

 slit. The nectaries on the leaves of B. edulis, previously described 

 by the same author, occur also in this species. 



2. Helicteres verhascifolia and spicata. — Nectariferous emergences, 

 which in H. spicata have a beautiful red colour at the base of the 

 flower-stalk. 



3. Turnera ulmifoUa — Emergences or growths of the periblem 

 at the base of the lamina of the leaf; morphologically, these are 

 leaf-teeth. 



4. Qiialea Gestasiana. — Saucer-shaped, short, cylindrical glands, 

 at the base of the leaf-stalk. 



The author also gives a description of the remarkable floral 

 nectary of Nelumho nucifera. 



Caltha dionaefolia, an Insectivorous Plant. 5 — This Antarctic 

 species was first described by Dr. Hooker, and the resemblance of its 

 leaves pointed out to those of Dioncea miiscipula. W. Behrens now 

 gives a fuller description of the structure, which is even more per- 

 fectly contrived for the capture of insects than that of Dioncea. 

 Both the margin of the lamina and the appendages to the leaf bear 

 numerous sharp, stiff teeth, pointed at right angles to the surface of 

 the leaf. The inside of the lamina is densely covered with viscid 



* See tills Journal, ii. (1879) p. 748, and iii. (1880) p. 114. 

 t Kosmos: Transl. in Rev. Sci. Biol., vii. (1881) pp. 4.50-65. 

 X Naturh. Foreu. videnskab. Meddelelser, 18S1 (1 pi.). Sec Bot. Ceutralbl., 

 vi. (1881) p. 7. 



§ Kosmos, ix. (1881) pp. 11-14 (7 figs). 



