Fig. 8.2-5. Transverse section of vascular bundle in stem of cosmos (Cosmos). The next few micrographs will be high magnifications of sieve tube members, and this medium power view is meant to help you get oriented. The companion cells are easy to identify, being very small and with dark red-stained contents (just a few of the many are indicated by arrows). The sieve tube members are most of the other cells in the phloem (all the tissue between the “Cambium” and the “Phloem fiber cap”).