28 TORREYA 



Denslow was read to the Club by the Corresponding Secretary. The Club voted 

 that a copy of this minute be sent to the family of the late Dr. Denslow. 



Whereas: Dr. Herbert McKenzie Denslow, a charter member of the Torrey Botanical 

 Club, President of the Club during the years 1928-1929, and Editor of its Bulletin during 

 the year 1924, died on September 7, 1944. 



Be it resolved: that we, the members of the Torrey Botanical Club, express our sense 

 of loss at his passing. His was a long and useful life, as pastor, teacher, and botanist. Born 

 on August 20, 1852, he early became interested in systematic botany through his uncle, 

 William Wallace Denslow (1826-1868). Both were charter members of the Torrey 

 Botanical Club, in 1867. Although an Episcopal minister and later a professor of pastoral 

 thology in General Theological Seminary, he always retained his enthusiasm for botanical 

 collecting, being especially interested in the native orchids ; a considerable list of published 

 papers on this subject bears witness to his industry. 



Resolved further: that a copy of these resolutions be sent to the members of his imme- 

 diate family. 



(Signed) Arthur H. Graves 

 John S. Karling 

 November 10, 1944 Edwin B. Matzke 



The scientific program consisted of an inspiring talk by Prof. R. H. Good- 

 win of Connecticut College on "Some Effects of Light upon the Growth and 

 Differentiation of the Oat Seedling." The speaker's abstract follows : 



The apical meristem of the germinating oat seedling is protected by the sheath-like 

 coleoptile as it is pushed to the soil surface by the elongation of the first internode — that 

 portion of the stem between the scutellar and the coleoptilar nodes. Elongation of the 

 internode is inhibited by light. 



Two distinct phases in the inhibition of elongation can be distinguished. The first is 

 characterized by high sensitivity to radiant energy and is due to the suppression of cell 

 division. The extent to which cell division is inhibited depends directly upon the amount of 

 radiant energy received by the plant. The second phase of the inhibition is characterized 

 by a much lower sensitivity to radiant energy and is due to a reduction of cell elongation. 



A study has been made of the development of vascular elements in the internode. 

 Annular, spiral, and pitted elements are successively differentiated, but the presence of 

 transitional types is emphasized. The first center of development of pitted elements arises 

 at the scutellar node and a wave of differentiation surges upward from this point through 

 the internode. A second center occurs later at the coleoptilar node, but the last portion to 

 show pitted elements is in the growing region just below the coleoptilar node. 



The rate of formation of spiral and particularly of pitted elements is greatly increased 

 after exposures to visible light, pronounced effects being observed as early as twelve hours 

 following weak irradiations. The close correlation between the light inhibition of elonga- 

 tion of the internode and the formation of pitted xylary elements which are incapable of 

 growth in length, is significant. 



The stimulus producing the inhibition of the internode may be received either by the 

 tip of the seedling — the coleoptile or the true leaves contained therein, or by the internode 

 itself. The internode exhibits a wide range of spectral sensitivity, being affected by wave 

 lengths ranging from the ultra violet to the infra red. In the completely etiolated seedling 

 carotinoids are abundantly present in the true leaves, but in other portions of the plant 

 pigments are present only in small amounts. True chlorophyll is apparently absent. But 



