﻿372 BOTANICAL GAZETTE [may 



a filament of four or five cells^ whose apical and basal cells are the last to 



divide longitudinally. 



The investigation traverses the account of Hypecoum given by Hegel- 

 niaier in 1878, and explains some of his inexplicable results, but at the same 

 time introduces a proembryo and suspensor without precedent among angio- 

 sperms. The behavior of the suspensor cells after their formation resem- 

 bles that found by Guignard among the Leguminosae. — J. M. C. 



A RECENT PAPER read by H. Marshall Ward ^^ before the Royal Society 

 gives the results of a detailed study of the histological features of the germi- 

 nation, infection, and growth of the mycelium of Uredo dispena in the tissue 

 of grasses. The research has been prolonged and has involved thousands of 

 preparations. The paper deals with the behavior of the nuclei, vacuoles, 

 septa, branches, haustoria, and other details of the hyphae up to the com- 

 mencement of spore formation. 



The relations of the hyphae to the cell contents of the host are critically 

 examined and the cumulative evidence not only fails to support Eriksson's 

 "mycoplasm" hypothesis, but is completely subversive of it so far as histo- 

 logical facts are concerned. Eriksson's hypothesis, which refers the epidemic 

 outbreaks of rust to the sudden transformation into the mycelial form of a 

 supposed infective substance, previously latent and invisible in the cytoplasm 

 of the host, is shown to be untenable because the corpiiscules speciaux of this 

 author are proved to be the cut-off haustoria of the fungus. Eriksson sup- 

 poses that these corpiiscules (haustoria) are formed by the hitherto latent 

 germs in the host-cells, growing up in the cells into vesicles, which then 

 pierce the cell-walls, and give rise to hyphae in the intercellular spaces. 

 The present paper shows that Eriksson has entirely reversed the true order 

 of events. The haustoria have been formed by the hyphae, and figures are 

 given showing every stage in their development. The first haustorium may 

 be formed by the infecting tube immediately after its penetration through 

 the stoma, and figures are given showing the remains of the germ-tube out- 

 side a stoma, the swelling of its tip over the stoma into an appressorium, the 

 passage through the stomatal cavity, and its development into a vesicular 

 swelling whence the true infection tube arises, which latter may at once put 

 forth a haustorium. In some cases all these latter phenomena are visible in 

 one and the same preparation. — J. M. C. 



Natha\sohn'3 has recently made what seems to be by far the most 

 important contribution to our knowledge of absorption and excretion which 

 has yet appeared. Working with Codium tomentostim, he finds that when the 

 plant is transferred from sea-water to a solution of NaNOg, absorption of this 



Ward, H. Marshall, On the histology of Uredo dispersa Erikss., and the 

 "mycoplasm" hypothesis. Read March 12, 1903. 



'^Nathansohn, Alexander, Ueber Regulationserscheinungen im Stoffaustausch 

 Jahrb. Wiss. Bot. 38: 241-290. 1902. 



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