294 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Colour of Apetalous Flowers.* — J. H. Lovell discusses the pre- 

 vailing colours of the apetalous flowers of the Northern United States 

 as evidence of their descent. He regards the apetalous Apopetalaa 

 (Saururaceae and Aizoaceae) as of primitive character ; they either are 

 or were autogamous or anemophilous. The absence of a blue colour 

 in the apetalous flowers is noteworthy. Yellow is not common, but 

 occurs in the scales and calyx of Betula. Ked is very common. A 

 number of genera have become entomophilous, and this has been accom- 

 panied by increased conspicuousness in the flowers. The anthers of 

 Salix, formerly anemophilous, have become a brighter yellow. In 

 Aristolochia and Asarum, the calyx is a lurid purple attractive to small 

 Diptera ; in Polygonum and several other genera it has become white 

 or red. 



Divergences in the Capitule of the Sunflower. f — Prof. S. Schwen- 

 dener gives a detailed account of a number of divergences from the 

 normal in the arrangement of the flowers in the capitule of the sun- 

 flower, from which he draws conclusions favourable to his view pre- 

 viously enunciated that the seat of formation of the primordia of the 

 flowers has not been determined a long while previously, but is regu- 

 lated step by step under the influence of the nearest older primordia. 



Ampbicarpous Plants.J — C. A. M. Lindman finds the following 

 amphicarpous plants in the flora of Southern Brazil: — (1) Cardamine 

 chenopodiifolia. The underground flowers are small, cleistogamous, 

 often with a reduced number of stamens, and evidently self-pollinated. 

 The underground pods are short (silicules rather than siliquse) and 

 abundantly fertile ; it is rare for the open aerial flowers to produce 

 seed. (2) Trifolium polymorphum. The underground flowers are small, 

 solitary, and completely cleistogamous ; they possess all the parts of 

 the open flowers, but reduced in number and size. The very short pods 

 contain one or two seeds. (3) Dichondra repens (Convolvulaceaa). The 

 small subterranean cleistogamous flowers are produced on the same 

 stems as the normal open flowers. (4) Callitriche deflexa. A terrestrial 

 epecies with both aerial and geocarpous fruits. 



Fruit-scales of Coniferae.§ — From the evidence afforded by pro- 

 liferous cones of the larch, and from the arrangement of the vascular 

 bundles in the scales of Abietineae, L. J. Celakovsky argues in favour 

 of his previously enunciated " axillary bud " theory, as supported by 

 Worsdell, || in opposition to the " placentar " theory of Delpino and 

 others. There are, he says, three kinds of greatly reduced axillary 

 shoots which deviate from the normal radiar type, passing over into 

 the leaf-like bilateral and dorsiventral type, viz. : — (1) Cladodes (Ruscus, 

 Danae, Semele) ; (2) Symphyllodes (scales of the cones of the Abietineaa 

 and of most other Coniferse) ; (3) Shoot-members (Sprossglieder), shoots 

 which are reduced not merely to one leaf, but to a single stem, to which 



* Amer. Nat., xxxv. (1901) pp. 197-212. 



f S.B. k. Prcuss. Akad. Wiss., xlvii. (1900) pp. 1042-60. Cf. this Journal, 1900^ 

 p. 481. 



X Ofv. k. Vetensk.-Akud. Forh., lvii. (1900) pp. 939-55 (4 figs.) (German). 

 § Pringslieiru's Jahrb. f. wiss. Hot., xxxv. (1900) pp. 407-48 (2 pis.). 

 U Cf. this Journal, 1900, p. 600. 



