44 Transactions of the Society. 



V. — The Glassijicatory Significance of Raphides in Hydrangea. 

 By George Gulliver, F.E.S. 



iRead 10th December, 1879.) 



In the last edition of Professor Lionel Beale's excellent book, ' How 

 to Work with the Microscope,' a brief notice, illustrated by two 

 plates, is given of some of my results concerning the value of 

 raphides as characters in systematic botany. Since that abstract 

 was written, I have been referring to my notes, extending over 

 several years of time and to many species of the order Saxifra- 

 gacefe, and in no case was there any appearance of raphides in 

 these plants. On the other hand, these beautiful crystals, within 

 their oval cells, are always abundantly present in Hydrangea. 

 Here then is a natural and sharp diagnostic between the Saxi- 

 frages and Hydrangeas. The raphides and their cells are easily 

 exposed by smashing up a bit of the leaf or young stem in a 

 drop of water on the object-plate, and still better by boiling a frag- 

 ment of the plant in a solution of caustic potass in a test tube over 

 a spirit lamp. A few minutes' boiling will suffice, and a very deep 

 object-glass is not required to bring the objects plainly into view. 



Though many of the best botanical systematists have long per- 

 sisted in arranging the Hydrangeas with the Saxifrages, other 

 eminent botanists, of whom the late Professor Lindley was one, 

 doubted the accuracy of this arrangement, and accordingly made a 

 distinct order of the Hydrangeas. Hence Lindley 's Hydrangeaceae. 

 And the present observations afford a new and unexpected addition 

 to the facts with which he supported his views. 



The Hydrangea hortensis is the deciduous shrub so common 

 in our gardens that it may be had for examination at any time. 

 This species was introduced from China to Britain upwards of a 

 century since. Another member of the genus. Hydrangea Thun- 

 hergii, affords in Japan a kind of tea so much esteemed that it is 

 called in that country Ama-toja, which means the Tea of Heaven. 



