May 28, 1920] 



SCIENCE 



549 



reservoirs of air and ocean. In the case of 

 dune plants tte root systems must go after 

 their mineral food supply and search the sand 

 grains for it. Not only this, they must con- 

 vert the needed portions of insoluble silicates 

 into soluble compounds suitable for absorp- 

 tion and metabolism. This they are well 

 equipped to do; for whatever other character- 

 istics various species of dime plants may have 

 and howsoever greatly they differ from one 

 another, they are alike in possessing extra- 

 ordinary root systems. This does not mean 

 that all the root sytems belong to one type or 

 class but that all are of relatively large 

 dimensions and well adapted to exploring for 

 their food supply or failing this to storing up 

 a supply by slow accumulations through the 

 year for a brief season of active growth or 

 short blooming period — for example, the bird- 

 foot violet (Viola pedata). The distances 

 which some of the longer roots travel, hori- 

 zontally, parallel with the surface, or in a 

 downward direction, are astonishing and all 

 but unbelievable unless one has traced such 

 roots by pulling them out; distances to be 

 measured in units of yards or rods rather than 

 feet or inches. Even quick-growing annuals 

 like sea kale {Cahile americana) will send out 

 horizontal root branches in length many times 

 the height of the plant — a plant ten inches 

 high may have horizontal root branches ten 

 feet long. 



For the determination of ash constituents, 

 seven typical species were selected. The sand 

 cherry (Prunus pumila), artemesia (Arte- 

 mesia caudata), black oak {Qvercus coccinea 

 iinctoria), the three grasses, Oalamovilfa, 

 Ammophila and Andropogon, and the scour- 

 ing rush {Equisetum hyemale var. inter- 

 medium) . 



The sand cherry sample consisted of stems 

 and a few leaves, the artemesia of stems, 

 leaves and seeds, the oak of a section of 

 trunk, the grasses of stems, leaves and seeds, 

 and the scouring rush of stems. These were 

 first carefully burned on clean iron pans to 

 a blackish or gray ash, then taken to the 

 laboratory and the ashing completed at a 



moderate red heat in muffles. The analyses 

 follow -.^ 



ANALYSIS OF ASH PROM ARTEMESIA AND PRUNUS 



Artemisia Prunua 



Silica 12.12 1.50 



Iron oxide (re,0,) 1.74 0.71 



Aluminum oxide (AljO^) 0.42 0.02 



Calcium oxide (OaO) 35.47 44.13 



Magnesium oxide (MgO) 6.41 4.25 



Phoaphlonic -anliydride (P.O.) 3.95 3.25 



Carton dioxide (CO,) 21.40 35.48 



Maagano-manganic oxide (MnjOi) 0.12 0.06 



Chlorine present as cMorides 1.75 0.26 



Sulphuric anhydride (SO,) 6.00 0.79 



Sodium oxide (Na^O) 0.52 0.40 



Potassium oxide (K,0) 11.61 10.94 



ANALYSIS OP ASH PROM QTJEKCUS ANB COMMERCIAL 



SAWDUST 



Saw- 



Quercu3 dust 



Silica 32.38 12.84 



Iron oxide 1.50 2.55 



Aluminum oxide 0.70 3.05 



Mangano manganic oxide (MugOj) 0.24 0.72 



Phosphoric anhydride 0.91 1.40 



Sulphuric anhydride 3.33 2.09 



Carbon dioxide 18.04 22.40 



Chlorine present as chlorides trace trace 



Calcium oxide 28.86 36.00 



Magnesium oxide 3.42 4.13 



Potassium oxide 9.51 13.39 



Sodium osiide 0.82 1.26 



ANALYSIS OP ASH PEOM FOUR DUNE PLANTS 



For comparison with the black oak ash, an 

 analysis was made of the ash on a sample of 

 ordinary commercial oak sawdust, source and 



« I am indebted to Messrs. L. S. Paddock and W. 

 B. Cochrane for the analytical work on the ash of 

 the various dune plants. 



