41 



DECEMBER. 



On Raphides in Ili/drangea Ilortcnsis, hy G. Gulliver, Esq., F.R.S. 



Happily the miovoscopo has now como iuto such common use 

 that any addition to tho manifold objects for it will liave more 

 or less inter, st ; and all the more so if they should bo always at 

 hand and ready for our ainusemont and instruction. Among 

 these is tho familiar garden sluub Hydrangea hortonsis. It is 

 throughout pervaded by raphides, of -which l)eautiful crystals, 

 about a score in a bundle, are contained in an oval cell, such 

 cells being scattered abundantly among the tissues of the plant, 

 and easily seen under a low object-glass, and still better under a 

 deep one. 



^iw Edgeworth originally mentioned to mo the prosonco of 

 true raphides in tho leaves of Hj'drangca. They may be readily 

 exposed by smashing ^ip a bit of the leaf in a drop of water on 

 tho object-plate. By boiling a fragment of tho 2)l:int in a 

 solution of caustic potass brings the rajihides and their cells 

 most distinctly into view ; and they may be further prepared 

 very well according to the processes recommended by our excel- 

 lent member, Mr. Hammond, which he described in " Science 

 Gossip," Jiine, 1878, and exhibited specimens of the results 

 thereof at former meetings of the Society. 



I5ut though interesting material for tlio microscope is thus 

 afforded by Hydrangea, tho raphides in this genus are note- 

 worthy in a taxonomic point of view. In former communica- 

 tions to the Society, and elsewhere, now summarised and illustra- 

 ted by two plates in the last edition of Professor Lionel 

 Beale's "How to Work with the Microscope," I have shown 

 how valuable raphides are as natural characters in sj-stematic 

 botany. And now they are further projiosed as significant in 

 relation to the position of Hj-drangea. Though manj'^ of the 

 best sj-stematists have long persisted in placing it with tho 

 Saxifrages, some other eminent botanists, of whom Lindley was 

 one, have doubted whether it belongs to this section, and, in- 

 deed, have seen nothing for Hj'drangea but a distinct order. 

 Hence Lindley's order Hydrangeaceae, chiefly distinguislied by 

 its opposite leaves. And now another and not less natural 

 diagnosis is proved ; for, according to my researches, the Saxi- 

 frages are destitute of raphides, while they abound in tlie 

 Hj'drangeas. Any person with a microscope may at once see 

 these facts very plainl^^ and see, too, in them a'u additional 

 argument for Lindley's conclusion. 



J lA-drangea hortensis, the deciduous shrub so commoTi in our 

 gardens, is a native of China, and was first introduced to Britain 

 in 1740. The order contains but few species of much economic 



