408 



SCIENCE. 



[N. S. Vol. XV. No. 376. 



an organ normally designed to store food 

 for the developing seedling may persist in 

 an emergency and take on a greatly in- 

 creased size for that purpose. The petiole 

 may assume a direction in connection with 

 its enlargement that will aid the blade in 

 its work of photosynthesis. Along with 

 these changes in the seed leaves there may 

 be others in surrounding parts, particularly 

 the hypocotyl which becomes thickened re- 

 markably and green in the morning glory 

 and gi-eatly elongated but slender in the 

 sunflower. In the radish a place for any 

 surplus growth still remains, for the root 

 is naturally destined to be fleshy and the 

 hypocotyl is not modified. 



Notes on New Species of Lichens collected 

 by the Harriman Expedition: Professor 

 Claba E. Cummings, Wellesley Col- 

 lege. 



The list, soon to be published, contains 

 an enumeration not merely of the species 

 collected by the members of the Harriman 

 expedition, but also of various other collec- 

 tions, notably that made by Professor 

 Setchell in Alaska the same year. The 

 total number of species and varieties listed 

 is 219. Of these 97 species are new to 

 Alaska, three of which are new to America 

 and three others new to science. The three 

 new species were referred provisionally to 

 the genera Yerrucaria, Endocarpon and 

 Pertusaria. The Verruearia was said to be 

 characterized by an unusual development 

 of the thallus. Three points of difference 

 from the typical Endocarpon were noted, 

 namely the distribution of the gonidia 

 throughout the tissue of the thallus, the 

 numerous perforations in the mature pro- 

 thallus and the projection of the apothecia 

 beyond both surfaces of the thallus. In 

 further discussion the possibility was stig- 

 gested that new genera might perhaps be 

 established for the so-called Verruearia and 

 Endocarpon. 



What is the Archesporium? Professor F. 



E. Lloyd, Columbia University. 



It is proposed to limit the use of the 

 term ' archesporium ' to the mass of cells 

 which, by tetrad divisions, gives rise to 

 spores. The cells heretofore so designated 

 have diverse origins and no peculiar mor- 

 phological features, and are distinguish- 

 able only by their denser cytoplasmic con- 

 tents. They are vegetative cells which are 

 set aside when an extensive archesporium 

 is necessary. It is only when the constitu- 

 ent cells enter the heterotypic mitoses that 

 their peculiar character is without doubt 

 evident. In parthenogenetically repro- 

 duced plants where true tetrad division in 

 this sense lapses, the archesporium is de- 

 termined on comparative grounds. 



The Continuity of Protoplasm: Dr. Henet 

 EIraemeb, Philadelphia College of Phar- 

 macy. (By title.) 



The earlier studies of the author upon 

 the structure of starch grains showed un- 

 der certain conditions the presence of radi- 

 ating feather-like clefts, which he con- 

 cluded represented channels through which 

 liquids are distributed throughout the 

 grain. Studies with similar reagents upon 

 cell walls seem to imply a similar nature 

 for many markings which have commonly 

 been explained as passages for permitting 

 the continuity of protoplasm from cell to 

 cell. He calls attention to references to 

 the use of sulphuric acid in the study of 

 continuity of protoplasm, and the objec- 

 tions to its emplojonent for this purpose. 

 The studies are being continued. 



The Embryology and Germination of the 

 Genus Peperomia: Professor Duncan S. 

 Johnson, Johns Hopkins University. 

 The ripe seed of this genus is about 

 .5 mm. long ; the globular, fifteen-celled em- 

 bryo only .04 mm. and the suri'ounding 

 endosperm .1 mm. in diameter. In germi- 

 nation the endosperm bursts out of the 



