. Botanical gazette. Plants. 230 BOTANICAL GAZETTE [SEPTEMBER The number of protoxylem points in the stem stele ranges from 4 to 11, with about 7 as the most frequent number. Sections of the young stem tip show the condition characteristic of Lycopo- dium, in which at about the time of differentiation of the proto- xylem points the metaxylem cells are distinguishable by their large size and lack of protoplasmic content (fig. 2). There are 3 so-called types of stele to be found in L. reflexum: the radial arrangement (fig. 3), the parallel-banded arrangement (fig. 4),. Fig. 5.—L. reflexum: stele
. Botanical gazette. Plants. 230 BOTANICAL GAZETTE [SEPTEMBER The number of protoxylem points in the stem stele ranges from 4 to 11, with about 7 as the most frequent number. Sections of the young stem tip show the condition characteristic of Lycopo- dium, in which at about the time of differentiation of the proto- xylem points the metaxylem cells are distinguishable by their large size and lack of protoplasmic content (fig. 2). There are 3 so-called types of stele to be found in L. reflexum: the radial arrangement (fig. 3), the parallel-banded arrangement (fig. 4),. Fig. 5.—L. reflexum: stele showing inner cylinder of xylem surrounding strand of phloem, most frequent arrangement found in stele of L. reflexum; X2cx>. and an arrangement consisting of an inner cyhnder of xylem sur- rounding a strand of phloem (fig. 5). These 3 arrangements of the xylem may be found in the same stem at different levels, and are all modifications of the radial arrangement. The parallel- banded arrangement, in which alternating strands of xylem and phloem occur in parallel bands across the cylinder, seems to be correlated to some extent with the growth of roots, since this arrangement is to be found most frequently in the region where the roots arise. The arrangement most frequently found is that consisting of an inner cylinder of xylem inclosing a strand of phloem (fig. 5). From this cylinder strands of xylem radiate to. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hanover, Ind. : J. M. Coulter
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