Anatomy of the Ophioglosseae . 
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Summary. 
1. The root of Ophioglossum vulgatum is monarch as regards 
its xylem, but the phloem has an indication of the presence 
of two protophloems. 
2. Monarch structure also occurs at the base of diarch 
rootlets in Ophioglossum pendulum and Botrychium Lunaria. 
3. The root-stele of Ophioglossum vulgatum has probably 
become monarch by reduction from diarch structure, viz. 
by the abortion of one of the xylem-g roups and the fusion 
of the two phloem-groups. 
4. A small amount of secondary thickening takes place 
in the root and stem of Ophioglossum vulgatum , xylem - 
elements only being added. 
5. Secondary thickening also occurs in the root-bases of 
Botrychium Lunaria . 
