170 



SCIENCE. 



[N. S. Vol. XIX. No. 474. 



An Ecologically Aberrant Begonia: Will- 

 iam Trelease. 



An account of a Mexican species of 

 Begonia possessing a single large sessile 

 leaf closely applied to the cliff on which 

 the plant grows, so as to afford protection 

 to its roots. 



Plant Formations in the Vicinity of Co- 

 lumbia, Mo.: Francis Daniels. 

 The vegetation of the region falls into 

 four main classes: (1) The aquatic and 

 subaquatic floras; (2) the mesophytic, or 

 in poor soil, xerophytic, sylvan flora; (3) 

 the rupestrine flora of the limestone cliffs; 

 (4) the cultural and ruderal floras. The 

 aquatic and subaquatic vegetation falls 

 into six zones: The aquatic, amphibious, 

 limose, ulignose (wet swamp), paludose 

 (open marsh) and riparian zones. The 

 mesophytic (or xerophytic) sylvan flora 

 assumes five main types: The alluvial, the 

 mesophytic sylvan proper, the open brush, 

 the arborescent glade and the sterile hill 

 type. The rupestrine flora exhibits four 

 types: The fontinal or dripping rock, the 

 soil-covered ledge, the bare rock and the 

 cliff summit types. The cultural and ru- 

 deral floras have the forms proper to pas- 

 tures, meadows, fields, orchards, gardens 

 and waste places. Besides these there are 

 a host of parasitic and saprophytic fungi, 

 and a few flowering plants, like Cuscuta, 

 Thalesia and Monotropa. 



The Distribution of Some loiva Plants; 



Formations on ivhich they Occur: L. H. 



Pammel. 



A brief account of some of the more im- 

 portant plants found on the carbonifer- 

 ous sandstone in eastern Iowa, noting the 

 occurrence of the white pine, Pinus Stro- 

 bus, Gaylussacia resinosa, Aspidiuni mar- 

 ginale, A. acrostichoides, Lycopodium 

 lucididum., Phegopteris Dryopteris, Dier- 

 villa trifida and Danthonia spicata. The 



occurrence of boreal types like Salix Can- 

 dida, Lobelia Halmii, Cnicus muticus, Geii- 

 tiana crinita. 



The Chemical Constituents of a Soil as 

 Affecting Plant Distribution: S. M. 

 Tracy. 



The author calls attention to the fact that 

 the distribution of plants is often attrib- 

 uted wholly to the physical and mechan- 

 ical condition of the soil, though in many 

 cases the chemical constituents of the soil 

 are equally potent. 



Vegetation of the North Shore of Lake 



Michigan: C. MacMilian. 



A brief sketch of the characteristic shore 

 and forest vegetation of the North Shore. 

 The strong resemblance of this to the 

 mountain vegetation of British Columbia 

 was pointed out. Not only does the re- 

 semblance appear in the many northern 

 species, but more particularly in the gen- 

 eral association of plants and the relative 

 preponderance of generic types. 



Zones of Vegetation About the Margin of 



a Lake: W. J. Bbal. 



About a mile and a half northwest of 

 Lansing, Mich., is a natural pond which 

 goes by the name of Jones' Lake with an 

 outlet at the west. The lake is nearly cir- 

 cular in outline and about forty rods in 

 diameter. There is a slight extension both 

 to the north and to the south. The bottom 

 and the shaky margins all around consist 

 uniformly of dark mud, ooze or muck. 

 The lake contains a few species of fish, 

 such as sunflsh, blue gills and spotted bass. 

 From the soft banks within two to three 

 rods, the bottom uniformly descends rap- 

 idly to deep water. I examined the mar- 

 gins of this lake on August 23, 1903. Be- 

 ginning with the deep water this is the 

 order of the bands of some of the leading 



