OPENING OF PALM SPATHES WITH AN AUDIBLE REPORT. 73 
hibited, Professor Gceppert, without loss of time, made another trans- 
verse cut, when again a report, though not so loud as the first, was 
heard. This experiment was then tried on a second very much smaller 
cone, and again a report was heard, though this time rather faint. 
Thinking that the cause might perhaps be sought in heat accumulated 
inside the spadix, a thermometer was inserted, but found not to be 
affected by this process. Professor Goeppert thinks that compressed 
air may perhaps be the cause of this singular phenomenon, but does 
not venture to pronounce an opinion in the absence of further experi- 
ments. As there are numerous large Cycads in England bearing cones, 
he hopes that his accidental observation may stand a fair chance of be- 
ing corroborated in this country." — Berthold Seemann. 
James Yates, Esq., F.R.S., to Dr. Seemann. 
* Lauderdale House, Highgate, March 9, 1862. 
“Although I have never seen or heard the explosion of which 
you speak in your letter to the ‘Gardeners’ Chronicle,’ I remember 
an occurrence in my collection of Cycads, which may assist in fur- 
nishing some answer to your question. In the year 1851, the large 
Encephalartus horridus, in my Palm-house, produced a cone of enor- 
aa dinensions.  It-is.a female. . 1a July the cone wee quite ma- 
ture. The rhomboido-peltate terminations of the scales had begun 
to separate, so as to show the orange-coloured drupes beneath them. On 
one occasion, when I went to look at the plant, I was surprised to find 
that the scales had fallen from at least two-thirds of the axis, and had 
evidently been projected from it with some force, since, besides being 
scattered on every side, some of them were enveloped and fixed among 
the leaves, In fact, it appeared to me that the cone had exploded. 
The modus operandi seemed to be the following :—When the proper 
period arrives, the scale separates from the axis exactly as a leaf sepa- 
rates from the branch on which it grows. Dr. Thompson, of Liver- 
pool, thinks this is effected by a deposition of starch at the place of at- 
tachment. However this may be, there is a natural joint at the base 
of the scale of a female Cycad, just as there is in leaves, and even in 
leaflets at their points of attachment to the stalk or branch. Whilst a 
preparation is thus made for the separation of all the scales from the 
axis, the drupes increase, so that their extremities, which are li 
towards the axis, press with more and more force against it. At 
