Mabch 18, 1910] 



SCIENCE 



435 



of the resin canals as centers. The resin is not 

 secreted within these cells and this supports 

 Tsehirch's view of resin secretion. 



The paper was illustrated by means of photo- 

 micrographs and diagrams. 

 The Origin of Natural Parks: Feedebio E. CI.EM- 



ENTS, University of Minnesota. 



During the past summer a special study was 

 made of the natural openings typical of many of 

 the mountain forests of Colorado. These so-called 

 parks range in size from hundreds of square miles, 

 as in South Park and San Luis Park, to a few 

 acres. They occur in practically every one of the 

 forest formations, and are themselves swamp, 

 grassland or chaparral of varying structure. This 

 was clearly found to be due to the fact that parks 

 are only stages in successions, the ultimate stage 

 of which is the surrounding forest in the great 

 majority of cases. Fire was found to be the most 

 frequent cause of the successions that produce 

 parks, while some the largest and most striking 

 are due to the filling of lakes with silt and plant 

 remains. Parks also follow the filling up of 

 canyons by sedimentation, while temperature and 

 migration are more or less frequent causes of 

 parks. 

 The Intensity of Alpine Light: Fkedeeic E. 



Clements and Feederic K. B"dttees, University 



of Minnesota. 



Readings were made during the past summer 

 in the Selkirk Mountains, on Mt. Rainier, and in 

 the Rocky Mountains of Colorado in accordance 

 with the same general plan. These were designed 

 to test the series of results obtained in Colorado 

 for a number of years, and to determine whether 

 mountain regions with higher humidity would 

 reveal greater absorption. The readings made in 

 the two regions are in close, if not complete, 

 agreement, and confirm the original conclusions 

 that alpine light is little if at all stronger than 

 the light at lower altitudes, and that it can not 

 be an efficient cause of alpine dwarfing. 

 The Morphology of a Remarlcaile New Cfymno- 



spermous Genus: E. C. Jeffeey, Harvard Uni- 

 versity. 



The genus is characterized by the possession of 

 the wood structure found in the araucarian genera 

 Araucaria and Agathis. It differs, however, 

 strikingly from these genera in the possession of 

 short shoots, which resemble rather those of 

 Ginkgo than those of Pinus. The short shoot, or 

 brachyblasts, persisted through many years and 

 their bases, embedded in the secondary wood of 



the main axis, in spite of their obvious perennial 

 character, present only a single zone of annual 

 growth. The short shoots were axillary to de- 

 ciduous leaves, the traces of which, unlike those 

 of Agathis, Araucaria and allied extinct genera, 

 do not persist in the secondary wood. The genus 

 is named Woodtcorthia. It constitutes one more 

 link between the abietineous and araucarian coni- 

 fers, which it is now apparent are connected by 

 annectent transitional forms. 

 Color Inheritance in Lychnis dioica: Geobge Hak- 



EisoN Shull, Station for Experimental Evolu- 

 tion, Carnegie Institution. 



Several years ago I showed that the purple 

 color of Lychnis dioica is a typical Mendelian 

 dominant character. It has since been found to 

 present several distinct grades of color, not noted 

 at first, but now shown to be due to distinct 

 Mendelian unit-characters. Most noteworthy of 

 these is a light bluish-purple tint due to basic 

 anthocyan, which is hypostatic to the correspond- 

 ing acid or reddish-purple anthocyan. Blue an- 

 thocyan has generally been found to be epistatio 

 to red in other cases. 

 Notes on the Behavior of Certain Hybrids of 



CEnothera in the First Generation: Beadlet 



Moose Davis, Cambridge, Mass. 



A demonstration and discussion of material 

 illustrating the characteristics in the first genera- 

 tion of the following hybrids of CEnothera: (1) 

 gigas X Lamarckiana, (2) murieata X gigas, (3) 

 muricata X grandiflora, (4) grandiflora X biennis, 

 (5) biennis X grandiflora. 



The characters of the parents, as presented in 

 each cross, were so blended that as regards the 

 measurements of parts, habit, texture of foliage, 

 etc., the average for each set of hybrids would 

 probably present a fair mean between the parents 

 concerned. There was, however, a wide range of 

 variation in the resemblance of the hybrids to one 

 or the other of the parents. 



No character of either parent was discovered 

 which appeared as dominant in these hybrids of 

 the Fi generation, after the manner which has 

 been described for certain forms (e. g., Pisum) 

 that illustrate most conspicuously Mendelian 

 dominance in the first generation. 



Some of the hybrids of each cross presented a 

 greater resemblance to one parent and some to the 

 other, and the forms could therefore be arranged 

 in two groups (twin hybrids) in one of which the 

 maternal characters were most evident and in the 

 other the paternal. There was no clear evidence 



