128 Field, Forest, and Wayside Flowers 
vessels. Transverse partition-walls separate one 
vessel from another, and these walls are sometimes 
horizontal and sometimes aslant. An inquiry into 
the names and uses of all these vessels would take 
one far into the mazes of structural botany. 
The student afield, with no equipment save a 
penknife and a pocket-lens, and with mayhap but a 
limited stock of patience, is content to know that this 
woody thread is a fibro-vascular bundle, and that 
its important parts are wood-vessels, bast-tubes, and 
tough fibres, which give strength and support to the 
whole affair. Further support is given to the fibro- 
vascular bundle of a monocotyledon or a fern by a 
bundle-sheath made of ,corky cells or of cells with 
very thick walls. 
The kin of the rose, too, form fibro-vascular 
bundles, and tough ones at that. When, in rid- 
ding the lawn of an intrusive plantain, one gives a 
pull to the tuft of leaves they are apt to tear away, 
leaving whitish strings dangling from the broken 
surfaces. These are the fibro-vascular bundles of 
the leaf-stem, and so are the strings, which must 
be removed from imperfectly-frosted table-celery. 
In the ‘‘wood”’ of a bundle are included all 
those vessels through which fluids ascend from the 
roots toward the leaves, 
