364 CouTANT: Woop PERIDERM IN CERTAIN: CACTI 
LITERATURE CITED 
_ 
. Kiister, E. Pathologische Pflanzenanatomie. Jena. 1903. 
. Lauterbach, C. Untersuchungen iiber Bau und Entwicklung der 
Sekrethehalter bei den Cacteen. Bot. Centralbl. 37: 257-264, 
289-297, 329-336, 369-375, 409-412. pl. 2, 3. 1889. 
. Schleiden, M. J. Beitrage zur Anatomie der Cacteen. Mém. Acad. 
Sci. St. Pétersbourg (Sav. Etrang.) 4: 335-380. pl. I-ro. 1839. 
. Solereder, H. Systematic Anatomy of the Dicotyledons. English 
translation. Oxford. 1908. 
Sorauer, P. Handbuch der Pflanzen-Krankheiten. 1. Berlin. 1909. 
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Explanation of plate 9 
All figures are Zeiss camera lucida drawings from hand sections, which, with the 
exception of that shown in Fic, 5, were taken transversely through the stem. In 
some cases. as noted. th -e * Cee eat Men rie _ 
Fic. 1. Section through the hypoderm and epidermis of stem of an Opuntia 
versicolor plant, stained with Bismark brown, X 730. a, epidermis; 6, outer layer 
of hypodermal cells, filled with calcium oxalate crystals; c, stomatal opening, leading 
down through hypodermal cells to cortical tissue; d, hypodermal cells; e, 
cortical 
tissue. 
1G. 2. Section taken near the periphery of a three-day-old wound in an Opuntia 
versicolor plant, X 245. a, cells ‘bordering on wound surface which have retained 
their starch content; b, outermost Portion of starchless layer, which has become 
t discolored; c¢, cells which will later divide, and so form the first wound- 
meristem; d, inner portion of starchless layer. 
Fic. Section from near the periphery of a seven-day-old wound in an Opuntia 
versicolor plant, X 390, a, starchless cells, with lignified walls; b, starchless cells, 
the walls of which give test for both lignin and suberin; c, suberized-walled cells 
which have arisen through the activity of the first wound-meristem; d, first 
meristem; e, “‘phelloderm" tissue, produced by first wound-meristem; 
cortical cells, 
Fic. 4. Section through a twenty-four-day-old wound of an Opuntia versicolor 
plant, stained with Bismark brown, 7 4, starchless cells, with lignified walls; 
wound- 
f, starchless 
cells, produced by first wound-meristem; d, inner mass 
of suberized-walled cells, produced through activity of first wound-meristem; ¢, 
first wound-meristem; f, “‘phelloderm” cells, produced by first wound-meristem. 
Fic. 5. Transverse optical section of lignified-walled cells, produced through 
activity of first wound-meristem, stained with phloroglucin and hydrochloric acid, 
X 390, a, cell lumen; 6b, middle lamella. 
1G. 6. Portion of wound-periderm produced in an Opuntia versicolor plant, 
injured thirty-one days; all tissues shown hav 
-walled cells; c, middle mass of suberized thin-walled 
cells; d, inner mass of lignified thin-walled cells; ¢, inner mass of suberized thin-walled 
cells, arising from first wound-meristem (not shown). 
