ZOOLOGY AND BOTANY, MICROSCOPY, ETC 559 



rootlets also increase in size and number ; the absorbent root-hairs 

 disappear, but the root-cap is well developed ; no mycorhizal swellings 

 are ever present. Such roots are frequently coloured owing to the 

 presence of chlorophyll and other pigments. The anatomy also under- 

 goes considerable modification ; the thickness of the bark is relatively 

 much increased and the piliferous layer disappears ; lacunae are formed 

 in the cortex, while the latter, together with the medullary rays, 

 undergoes lignification ; the number of vascular bundles is greatly 

 reduced. The secondary roots are characterized by the relative abundance 

 of the lenticels and the diminution in the number of vascular bundles 

 and amount of sclerenchyma and other supporting tissues. 



The action of water rests upon two factors, viz. its physical and its 

 chemical properties. Thus, its homogeneity produces equality and 

 symmetry of growth, and the support afforded to the roots causes, on 

 one hand, a reduction in supporting tissues, and, on the other, a forma- 

 tion of lacunas, whereby the root is enabled to float more freely. The 

 solvent property of water facilitates the absorption of food-materials, and 

 consequently causes a reduction in the absorbing and conducting tissues ; 

 also, since absorption can take place at any part of the root-surface, 

 lenticels are abundant. 



CRYPTOGAMS. 



Pteridophyta 



(By A. Gepp, M.A. F.L.S.) 



Macroglossum.*— D. H. Campbell publishes notes on the structure 

 of Macroglossum, a new Marattiaceous genus described by E. B. Copeland 

 in 1909, and containing one species, M. Alidse. Campbell finds a second 

 species in the type plant of Angiopteris Smithii Racib., cultivated in the 

 Buitenzorg botanic garden, but of unknown origin. The latter is a 

 somewhat smaller species. The fronds of Macroglossum are upright and 

 simply pinnate ; those of Angiopteris are broad-spreading aud bipinnate. 

 In habit Macroglossum much resembles the larger species of Dansea. 

 Campbell describes and figures the structure of the lamina, indusium, 

 sorus, sporangium, and annulus of Macroglossum, and contrasts them 

 with those of Angiopteris and other genera. 



Vittaria.t — R. C. Benedict publishes a revision of the genus Vittaria. 

 Having in a previous paper (in 1911) discussed the morphological 

 features of the tribe Vittarieaa, and indicated the probable relationships 

 of the genera, he now treats of seven species comprised in his sub- 

 genus Radiovittaria, which is characterized by its radial stem structure 

 and leaf arrangement, as well as the specialized collenchyma. He has 

 found it necessary to study the plants microscopically and make sections 

 of the stems and leaves. It is then seen that there are very consider- 

 able differences in the outline of the transverse sections of the leaf, 



* Philippine Journ. Sci. (Bot.) ix. (1913) pp. 219-25 (1 pi. and figs.), 

 t Bull. Torrey Bot. Club, xli. (1914) pp. 391-410 (6 pis. and figs.). 



