thorny question

Thomas Lammers lammers at VAXA.CIS.UWOSH.EDU
Wed May 17 10:26:30 CDT 2000

At 06:59 AM 5/17/00 -0700, you wrote:
>If thorns are often modified leaves with photosynthetic tissue, maybe it's
>where ps and respiration occurs. Also, when thorns are modified epidermal
>structures, often they are filled with chloroplasts; perhaps w/similar

My impression is that most spines, prickles, and thorns do not contain
chloroplasts and so do not contribute to primary productivity.  This is
certainly correct in the cacti, rose prickles, and locusts.  However, you
are correct about leaf morphology in general in more xeric environments.

Thomas G. Lammers, Ph.D.

Assistant Professor and Curator of the Herbarium (OSH)
Department of Biology and Microbiology
University of Wisconsin Oshkosh
Oshkosh, Wisconsin 54901-8640 USA

e-mail:                     lammers at
phone (office):         920-424-7085
phone (herbarium):  920-424-1002
fax:                         920-424-1101

Plant systematics; classification, nomenclature, evolution, and
biogeography of the Campanulaceae s. lat.
"Today's mighty oak is yesterday's nut that stood his ground."
                                                 -- Anonymous

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