TRANSACTIONS OF SECTION K. 751 



bear not one but three ovules. They are considered to represent the cone-scales of 

 the femnle cones of Brachyphyllum. These scales have been referred to a new 

 genus, Protodammara. They possess a double system of bundles of opposite 

 orientation and show no indication of the presence of anything comparable to 

 a ligule. The lower series of bundles, corresponding probably to the fused sterile 

 bract, which mnny authors accept as the morphological equivalent of the free bract 

 •which is found in the Abietineae, are in their upper portions surrounded by zones 

 of transfusion tissue which, like those in the leaves of Brachyphyllum, become 

 confluent. 



The wound-reactions of Brachyphyllum are strikingly similar to those of the 

 Abietineae, for in three different species of thia genus from Staten Island, Martha's 

 Vineyard, and the Potomac, it has been observed that traumatic resin-canals are 

 the result of wounds, just as they are in Abies, &c. The occurrence of traumatic 

 resin-canals is confined to Brachyphyllum, and is not found in other Cretaceous 

 Araucarians, or in the living Agathis and Araucaria. This feature will be 

 recognised by those who are familiar with the structure of coniferous woods as 

 one of great importance. 



Brachyphyllum, although undoubtedly Araucarian in its alBnities, resembles 

 the Abietineoe : (1) in the structure of its wood, (2) in the structure of the 

 phloeaj, (3) in the organisation of its leaf traces, (4) in the features presented 

 by its wound-reactions. The coiie-scales, which have been referred by Dr. Arthur 

 Rollick and the writer to the new genus Protodammara, probably belong to 

 Brachyphyllum, and represent a more reduced type of anatomical structure than 

 that found in the Abietinere. Brachyphyllum appears to remove the Araucarinefe 

 from a position of isolation, and to show them as undoubtedly coniferous and allied 

 to the Abietinere. 



3. Zygospore Germiiiations in the Mucorinece} 

 By k.'E. Blakeslee, Ph.D. 



The zygospores of the Mucorineae require a longer or shorter period of rest 

 before they become capable of germination. 



The germination of the zygospores of the bomothallic species Sjjorodinia is 

 pure bomothallic. 



In the germination of the zygospores of the heterothallic species Mucor 

 Mucedo, the segregation of sex is completed at some time before the formation of 

 sporangial spores, and all the spores in a given germ sporangium are of the same 

 strain, either ( + ) or ( — ). 



In the germination of the heterothallic species Phycomyces nitens, a segre- 

 gation of sex may take place at the formation of spores in the germ sporangia, 

 but is only partial. In addition to ( + ) and ( — ) heterothallic spores, spores are 

 formed which give rise to bomothallic mycelia characterised by a production of 

 spirally coiled aerial outgrowths termed pseudophores and the occasional forma- 

 tion of bomothallic zygospores. A bomothallic mycelium also may be obtained 

 by bringing the germ tube to branch out to a mycelium before the formation of 

 the germ sporangium. 



The sexual character in these bomothallic mycelia is unstable, and in their 

 sporangia a segregation again takes place and ( + ),( — ), and bomothallic spores 

 are produced. 



The germination of the bomothallic zygospores is of the same type as that of 

 the heterothallic zygospores, and no fixation of the bomothallic character takes 

 place. 



' Annates Mycologici, vol. iv. No. 1, 1906. A ;Eeport as Research Assistant of 

 the Carnegie Institution. 



