THE society's NOTE-BOOKS. 43 



to produce false or unnatural crystals in them ? In many leaves 

 which I have bleached I have noticed, besides the natural Raphides 

 and Sphseraphides, numbers of small crystals, some irregular in 

 shape, like very small Sphseraphides and some larger, giving beau- 

 tiful rosette-like appearances with polarised light. I am convinced 

 that false crystals are produced if a solution of chloride of lime is 

 used, particularly the rosette-shaped ones, and I am afraid that the 

 same thing takes place sometimes with the soda solution. 



W. H. Hammond. 



I agree with the possibility of the above taking place, but have 

 not yet seen any evidence of its actual occurrence. It would be 

 more likely to happen with lime, as soda salts are far more soluble 

 than those of lime, and would be probably washed away in the free 

 rinsings which the process of preparing involves. 



G. D. Brown. 



[We think a weak solution of acetic or nitric acid in the last 

 washing but one, would effectually get rid of any traces of either 

 soda or lime that might be adhering to the leaves. — Ed.] 



EXPLANATION OF PLATES III., IV., V., VL, VIL, VIIL 



Plate III. 



Fig. 1. — Plagiogramma elongatum. 



a. — Side view of an ordinary-sized specimen, mag. 250 diam. 

 h. — Side view of another specimen (I sporangial). 

 c. — Front view ; outline of missing valve supplied. 



,5 2. — Hydrodictyon utriculatum. 



a. — Natural size of the specimen. It is said to grow from 4 

 to 6 inches in length, and I think I have seen a pressed 

 specimen reaching nearly to this latter size. 



6. — Portion magnified 15 diameters. 



c. — Another piece, magnified 50 diameters, to show the knots 

 at the junction of the cells. 



,, 3. — The specimen of Goleosporum tnssilaginis. 



a. — Restored to its natural appearance. The outline of the 

 leaf gives the position from which it has probably been 

 taken. 

 6. — Echinulate spores ; the early or Uredo form of fruit, 

 c. — Four-septate ascus. 



,, 4. — Stellate hairs from Niphoholus lingua. 



