504 SUMMARY OF CURRENT RESEARCHES RELATING TO 



since no parasite, either animal or vegetable, was detected in another 

 small branch where similar growth was just beginning. 



Medulla-cells of Lammariacese.* — M. G. Thoday describes and 

 figures a reticulate thickening which occurs in the walls of the cells of 

 the medulla in Laminariacese. It was well-developed in the walls of 

 both the primary pith-filaments and the hyphse, but was not present in 

 the much thinner walls of the secondary sieve-tubes. After various ex- 

 periments she found that the thickenings depended entirely on the 

 methods followed in preserving, staining, mounting, etc., and are due 

 to wrinkling consequent ou partial dehydration ; and since they begin 

 to appear after very slight drying, they afford a remarkable indication of 

 the very mucilaginous nature of the longitudinal walls of the medulla- 

 cells in their normal state. At the base of the stipes, where all the 

 cell-walls of both cortex and medulla become much thickened and car- 

 tilaginous, this wrinkling does not occur on drying. 



Fructification of Macrocystis.f — E. J. Hoffmann discusses the geo- 

 graphical distribution of Macrocystis pyrifera, and describes the results 

 of her studies on the fructification. She gives a resume of the work of 

 previous authors, and shows that some of them have arrived at erroneous 

 conclusions evidently through studying wrongly named material. The 

 author states that the fructification is found, not only on newly- 

 formed unsplit bladderless basal leaves, but also on branched leaves, with 

 or without a bladder, such leaves occurring near the holdfast of the plant. 

 The sori are not in furrows, but in wide patches on both sides of the leaf, 

 and consist of paraphyses and zoosporangia. 



Ahnfeldtia gigartinoides. +— A. S. McFadden discusses the nature 

 of the carpostomes in the cystocarp of Ahnfeldtia gigartinoides. The 

 cystocarp is the only form of fruit known in this species ; and in each 

 cystocarp are formed some forty carpostomes, or long narrow irregular 

 slits which pass through the anticlinal layers of the pericarp. The carpo- 

 stomes are filled with several-celled filaments, which are projections of 

 the cells of the anticlinal rows. The origin of the carpostomes is doubt- 

 ful, but there seem to be indications that these slits are formed by 

 decomposition. She also discusses the difference between A. gigartinoides 

 and A. concinna. 



Erythrophyllum delesserioides.§ — W. C. Twiss writes on the struc- 

 ture and development of the papillas and cystocarps of Erythrophyllum 

 deles serio ides, and describes them in detail. As a result of his studies, he 

 comes to the conclusion that this alga, by virtue of the character of its 

 fruiting proliferations, its so-called compound cystocarp, with spore- 

 groups separated from each other by partitions of vegetative cells, and 

 by virtue of its vegetative structure, belongs among the Gigartinacere, 

 as Agardh at first stated. Furthermore, the character of the carpogenic 

 branch, and the method of spore-formation, only strengthens the belief, 

 which the vegetative structure at once suggests, that its place, according 

 to the present classification, is very near to the Callymeniere. 



* New Phytologist. x. (1911) pp. 68-70 (figs, in text). 



t Univ. California Publications (Bot.) iv. (1911) pp. 151-8 (lpl.). 



j Univ. California Publications (Bot.) iv. (1911) pp. 137-42 (1 pi.). 



§ Univ. California Publications (Bot.) iv. (1191) pp. 159-76 (-4 pis.). 



