ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 273 



Anatomy of Cheilantkes and Pellaea.* — A. S. Marsh has made an 

 anatomical study of certain xerophilous species of Cheilantkes and 

 Pell sea : — 1. The xerophilous species of these genera show well-marked 

 leaf adaptations — such as hairs or scales on the lower surface, inrolled 

 margins, thick cuticle, and palisade parenchyma. 2. The Cheilantkes 

 species, all belonging to the section Pkysapteris, show a wide range of 

 stelar anatomy in their stems. Details of these are given. 3. In 

 Pel/sea one xerophytic species was examined, P. andromedsefolia. 4. 

 The petiolar structure, the stem anatomy, and the greater output of 

 spores per sporangium all point to C. Fendleri as a near approximation 

 to an ancestral type from which 0. gracillima and C. lanuginosa have 

 been derived. 



Anatomy of Helminthostachys.f — W. H. Lang publishes a detailed 

 paper on the anatomy and branching of the rhizome of Helminthostachys 

 zeylanica. His long summary is difficult to compress : — 1. The rhizome 

 of Helminthostachys exhibits a general segmental construction — two 

 dorso-lateral and one ventral segment. The former correspond with the 

 leaf-insertions. The ventral segments bear no leaves. Internodes are 

 not evident in the adult plant. The relation between segmental con- 

 struction of the rhizome and cell-segmentation at the apex is not traced 

 out. 2. The stele of the adult- rhizome has a large pith in a tube of 

 mesarch xylem. 3. The roots are endogenous and penetrate a thin 

 cortex. Their xylem is continuous with the outer xylem of the rhizome 

 stele, and sometimes the pith is also continuous. 4. The dorsal side of 

 the stele is disturbed by the leaf-traces and in relation to the vestigial 

 buds. The leaf-trace exhibits considerable variety in its mode of 

 departure, structure, and mode of division in the cortex. For instance, 

 whether mesarch or endarch, the leaf -trace may divide into two in the 

 cortex without adaxial completion of the outer xylem or the other 

 tissues ; but more usually it is complete before division. 5. The dis- 

 turbance of the stele in relation to the vestigial axillary buds varies in 

 degree, being most marked in large adult rhizomes. In all cases the 

 endodermis remains open ; and there may be a bulge of xylem behind 

 the bud. The vestigial bud is in relation to the subtending leaf, and is 

 somewhat variably situated relatively to the leaf -gap. 6. The vascular 

 relations of two branches, developed from lateral buds, to their parent 

 rhizomes are described, and place the nature of the dormant buds 

 beyond doubt. 7. The inner xylem is unequally developed at different 

 levels in the adult rhizome, and exhibits a gentle rhvthm of decrease 

 and increase in the dorsal region of the stele. It diminishes or disap- 

 pears opposite the nascent leaf-trace, and is very strongly developed as the 

 leaf-gap closes. 8. The structure of slender rhizomes with the juvenile 

 type of stele, is described both for plants developed from the embryo 

 and for branches. 9. The juvenile type of anatomy may be maintained 

 for many nodes. The transition from the seedling structure to the 

 adult type has not been studied. 10. The juvenile type of structure is 



* Ann. Bot., xxviii. (1914) pp. 671-84 (figs.). 



t Ann. Bot., xxix. (1915) pp. 1-54 (3 pis. and figs.). 



