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  Missing Raphides
From: Ted.Held at hstna.com on 2001.07.05 at 21:48:54(6961)
I read Deni Bown's chapter "Acids and Crystals" with rapt attention
[Aroids, 2nd Edition, Deni Bown, Timber Press, 2000]. I saw the
illustration of dumbcane raphides on page 279 and resolved to photograph
them with a scanning electron microscope. I had a handy dumbcane (looks
like the variety of D. seguine labelled "Candida" in Plate 40 from that
book) and I cut a stem and caught some of the sap from the wound. When the
sap was dry I looked at it under the electron microscope. There are
numerous polygonal structures (crystals?) about 1 micron in size. But these
are blunt, not at all like the sharp needles I had hoped to see. I found no
evidence of anything like the raphides described in the book. She says
raphides should be about 150 to 300 microns in length and 8 to 15 microns
in diameter. So I have plenty of resolution to see something that size.
Does anyone know what I did wrong?

If you wish to see the picture I made of the dried dumbcane juice you can
contact me directly. I will e-mail you the picture. The file is about 1.25
megs and is in black and white. It is of interest even if there are no
raphides.

ted.held@hstna.com

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