512 SUMMARY OF CURRENT RESEARCHES RELATING TO 



done on specialization and on immunity, and these papers also are 

 passed under review. A complete bibliography is appended. 



W. B. Grove * has published a paper on the " Evolution of the 

 Higher Uredine^e," in which he traces development from primitive 

 ancestors with only one spore-form, an ascidio-teleutospore. Uredo- 

 spores were intercalated later. The formation of the heteroecious habit 

 would " demand a sudden but not inconceivable mutation, of which 

 evidence will yet be found." From complete autoecious species he 

 considers that brachy- and micro-forms might arise by the dropping 

 out of spore-forms. The spermogones he considers to be primitive, and 

 every view of evolution must take them into account along with correla- 

 tive female cells. 



Formation of Giant Cells in Aspergillus fumigatus.f — C. 

 Wehmer has observed that in old cultures of this fungus in sugar and 

 inorganic salts, the superficial layer of conidia sinks below the surface, 

 and that the character of the fungus cells changes, as they take on very 

 large proportions. He observed further that this chauge only occurred 

 in acid conditions of the nutritive medium. Wehmer discusses the 

 significance of the phenomenon and the nature of the cell-walls of the 

 large cells. 



Leptostromaceae.J — H, Diedicke has made a morphological and 

 comparative study of the genera of this family. He gives a list of 

 species that cannot be included, describes two new genera, Pycnotlu/rium 

 and Thyriostroma, and then gives a more minute account of the charac- 

 istics of the family. The fruiting body consists usually of a very thin 

 peridium, enclosing slender sporophores and minute hyaline spores. 



Morphology and Development of Phoma RichardiaB sp. n.§— AV. 

 B. Mercer has taken the opportunity of making a large series of cultures 

 with a Phoma, which he found on decaying leaves of Richardia afrkana. 

 It is not parasitic. He was unable to connect it with any higher fruit- 

 ing form, but he obtained from the spores two kinds of conidial fructi- 

 fications — a species of Alternaria not hitherto described, and gemmae 

 which were developed on mycelium in old cultures. 



Mercer finds that the pycnidia originate in two ways : (1) by the 

 weaving together and profuse branching of hyphse to form a dense 

 cellular mass or primordium ; and (2) by the repeated division of a few 

 adjoining cells of a hypba, usually aided by the fusion of short branches. 

 Under certain circumstances the pycnospores may divide in this manner 

 and directly form pycnidia. Mercer lias suggested that the fungus 

 secretes a substance poisonous to itself. 



Dry-rot in Building Timber. |1 — R. Falck has published a mono- 

 graph of MeruHus as it affects timber. The different species of the 



* New PhytoL, xii. (1913) pp. 89-106. 



t Ber. Deutsch. Bot. Gesell., xxxi. (1913) pp. 257-68 (7 figs.). 

 t Ann.MycoL, xi. (1913) pp. 172-84 (10 figs.). 

 § Glycol. Centralbl., ii. (1913) pp. 297-305, 326-31 (6 figs.). 

 II Die Merulius-Faule des Bauholzes. Jena : Gustav Fischer (1912) xvi aud 

 405 pp. (17 pis. and 73 figs.). See also Zeitschr. Bot.. v. (1913) pp. 579-82. 



