564 SUMMARY OF CURRENT RESEARCHES RELATING TO 



species, nor even for a hybrid. The indusiuni of A. Ruta-muraria is one 

 of the most typical characters of the species ; it is longly ciliate. And 

 yet, curiously enough, authors have described it so diversely as erose, 

 denticulate, lacerate, fimbriate, etc. (scores of citations are given in foot- 

 notes) ; and in their figures they have almost all either omitted it or 

 represented it as entire, crenulate, eroso-lacerate, denticulate, or very 

 shortly ciliate. Pampanini has, by numerous observations, determined 

 it to be more or less longly ciliate at first, the cilia equalling the width 

 of the undivided part of the indusium or even being twice as long. 

 After maturation of the spores, the cilia break off, and the membrane 

 becomes lacerate. Figures are given. 



How Ferns Grow.* — M. Slosson, in her freely illustrated book 

 " How Ferns Grow," points out the principal features of the develop- 

 ment of form and venation in fronds as seen in the ferns of the North- 

 Eastern United States. Eighteen species are treated, each in a chapter 

 by itself, containing a description of a mature plant followed by a 

 detailed account of the evolution of the fronds from the earliest simple 

 form of the first year, to the fully developed frond of a mature plant. 

 Sufficient examples of these often strangely diverse stages occurring in 

 one and the same species are well represented by photography in the 

 plates. 



Structure of Tree-Ferns.f — W. Schiitze treats of the physiological 

 anatomy of some tropical ferns, especially the tree-ferns. He gives a 

 brief summary of such little work as has been done on this neglected 

 subject, and attempts to supply in this paper such information as 

 botanists require. His material comprises the genera Cyathea, AhopMla, 

 Hemitelia, and Dicksonia, and also Lygodium and Drimoglossum. First 

 he treats of the epidermis, the corky sub-epidermal layers, and epidermal 

 structures. Passing on to the vascular tissue, he describes the form and 

 course of the main bundle, of the medullary and cortical bundles, the 

 hadrome and protohadrome, tylosis, the leptome and protoleptome, the 

 parenchyma sheath and endodermis, the external parenchyma. He then 

 deals with the mechanical system, its structure and arrangement, the 

 mechanical cells, the brown colouring-matter in the walls of the un- 

 lignified stereome-cells ; and concludes with remarks on the secretory 

 system and the stores of excreted matters. 



Bud-formation on Fern-leaves. J — W. Kupper treats of the forma- 

 tion of buds on certain fern-leaves, especially Adiantum Edgeworthii. In 

 this and some seven other species apical buds occur. He discusses the 

 various modes of development of the buds in relation to the leaf -apex. 

 The bud-bearing leaves usually are prolonged at the apex, so that the 

 bud is made to touch the earth and takes root as an independent plant. 

 The author describes the various modifications of the first leaves of the 

 buds formed by the different species. In Trichomanes pinnatum buds 

 are produced on each side of the lengthened rachis in place of pinnge, 

 and arise like these from marginal cells. In Asplenium obtusilobum and 



* New York : Henry Holt, 1906, viii. and 156 pp., 46 pis. 

 t Beitr. wiss. Bot., v. (1906) pp. 329-76 (figs.). 

 % Flora, xcvi. (1906) pp. 337-408 (figs.). 



