Origin and development of tissues in Equisetum scirpoides
by Johnson M. A. (1933)
Marion A. Johnson
Hull Botanical Laboratory
in Bot. Gaz. 94 : 469-494. –
1. The first periclinal division in each segment from the apical cell of the stem separates pith and “primary cortex,” which in turn gives rise to stele and cortex.
2. The pericycle, endodermis, and one or two layers of the inner cortex of the stem are stelar in origin.
3. Evidence is presented for regarding the so-called inner endodermis of the root as pericycle.
4. The endodermis and pericycle of the root are of cortical origin.
5. Dormant branches occur as in other species of Equisetum. They are exogenous in origin. 6. The first root developed by the branch is endogenous.
7. The stelar parenchyma in the root is much reduced.
8. Hydathodes of the water stomata type occur on the upper surface of the leaves.
9. Rare but well-developed tyloses are found in the carinal canals.
10. Reduction in xylem is extreme, the supranodal wood being frequently absent above the leaf traces, forming a gap in the xylem.
11. The gaps in the xylem of the cone are correlated with the size of the stele and failure of the fundamental tissue to develop.