VI 
Index. 
PAGE 
Skene, Macgregor. —The Acidity of Sphagnum and its Relation to Chalk and Mineral Salts 65 
Small, James. —The Pollen-presentation Mechanism in the Compositae. With seven Figures 
and two Tables in the Text .......... . 457 
Spratt, Ethel Rose. —The Root-Nodules of the Cycadaceae. With Plate XXIX . . 619 
Stiles, Walter. — On the Relation between the Concentration of the Nutrient Solution and 
the Rate of Growth of Plants in Water Culture ........ 89 
-and Jorgensen, Ingvar. —Studies in Permeability. I. The Exosmosis 
of Electrolytes as a Criterion of Antagonistic Ion-action. With fourteen Figures in 
the Text ... ......... ... 349 
-■-- Studies in Permeability. II. The Effect of 
Temperature on the Permeability of Plant Cells to the Hydrogen Ion. With four 
Diagrams in the Text.611 
Welsford, E. J. — Nuclear Migrations in Phragmidium violaceum. With Plate XVI . . 293 
West, Cyril. —On the Structure and Development of the Secretory Tissues of the 
Marattiaceae. With Plate XVIII and fourteen Figures in the Text .... 409 
- and Lechmere, Arthur Eckley. —On Chromatin Extrusion in Pollen 
Mother-cells of Lilium candidum, Linn. With Plate XV ..... 285 
Willis, J. C.—The Origin of the Tristichaceae and Podostemaceae.299 
Wilson, Malcolm. —Sex Determination in Mnium hornum. With Plate XX . . . 433 
Woodburn, William L.—Spermatogenesis in Mnium affine, var. ciliaris (Grev.), C. M. 
With Plate XXI.441 
Woolery, Ruth. —Meiotic Divisions in the Microspore Mother-cells of Smilacina racemosa 
(L.), Desf. With Plate XXII and one Figure in the Text . . . . .471 
Worsdell, W. C.—The Origin and Meaning of Medullary (Intraxylary) Phloem in the Stems 
of Dicotyledons. I. Cucurbitaceae. With ten Figures in the Text .... 567 
B. LIST OF ILLUSTRATIONS. 
a . Plates. I-III. 
IV, V. 
VI. 
VII. 
VIII. 
IX, X. 
XI. 
XII-XIV. 
XV. 
XVI. 
XVII. 
XVIII. 
XIX. 
XX. 
XXI. 
XXII. 
XXIII. 
XXIV, XXV. 
XXVI, XXVII. 
XXVIII. 
XXIX. 
Studies in the Morphology and Anatomy of Ophioglossaceae (Lang). 
Comparison of the Stem Anatomy of the Cohort Umbelliflorae (Hoar). 
Obligate Symbiosis in Calluna vulgaris (Rayner). 
Observations on the Germination of the Spores of Coprinus sterquilinus, 
Fr. (Baden). 
Effect of Salt on the Growth of Salicornia (Halket). 
Comparative Morphology of the Embryo and Seedling in the Gramineae 
(Sargant and Arber). 
Branching and Branch Shedding of Bothrodendron (Lindsey). 
A Second Contribution to our Knowledge of the Anatomy of the Cone 
and Fertile Stem of Equisetum (Browne). 
On Chromatin Extrusion in Pollen Mother-cells of Lilium candidum, 
Linn. (West and Lechmere). 
Nuclear Migrations in Phragmidium violaceum (Welsford). 
Observations on the Osazone Method of locating Sugars in Plant Tissues 
(Mangham). 
On the Structure and Development of the Secretory Tissues of the 
Marattiaceae (West). 
On Glaucocystis Nostochinearum, Itzigsohn (Griffiths). 
Sex Determination in Mnium hornum (Wilson). 
Spermatogenesis in Mnium affine, var. ciliaris (Grev.), C. M. (Woodburn). 
Meiotic Divisions in the Microspore Mother-cells of Smilacina racemosa 
(L.), Desf. (Woolery). 
The 1 Endoconidia ’ of Thielavia basicola, Zopf. (Brierley). 
Studies in the Phylogeny of the Filicales (Bower). 
A Contribution to our Knowledge of Rachiopteris cylindrica, Will. 
(Bancroft). 
The Root-nodules of Ceanothus americanus (Bottomley). 
The Root-Nodules of the Cycadaceae (Spratt). 
