Ectophloic siphonostele is found in (a) Osmunda and Equisetum (b) Marsilea and Botrychium (c) Adiantum and Cucurbitaceae (d) Dicksonia and Maiden hair fern.
Option AStele is a column containing vascular tissues which is surrounded by pericycle and separated from ground tissue by endodermis. Siphonostele is medullated protostele or protostele with a central nonvascular pith. Leaf gaps are absent. Siphonostele is of two types : In Ectophloic siphonostele, central pith is surrounded successively by xylem, phloem, pericycle and endodermis. In amphiphloic siphonostele there is a central pith and xylem is surrounded on either side by phloem, pericycle and endodermis. It is found in Osmunda and Equisetum.
