Ectophloic siphonostele is found in

Explanation

a. Osmunda includes various species of ferns, such as the royal fern, which exhibit an ectophloic siphonostele. This means that their primary phloem surrounds the primary xylem, which is a characteristic of some ferns. Equisetum refers to horsetails, a different group of vascular plants. While horsetails do exhibit a siphonostele, they have a different vascular arrangement. Some horsetails, like Equisetum arvense, have a protostele (central vascular cylinder), which is not the same as an ectophloic siphonostele. The other options do not accurately describe plants with ectophloic siphonosteles: b. Marsilea and Botrychium: Marsilea and Botrychium are fern genera, but they are not typically associated with ectophloic siphonosteles. They have different vascular arrangements. c. Adiantum and Cucurbitaceae: Adiantum is the genus of maidenhair ferns. While they are ferns, they do not typically have ectophloic siphonosteles. Cucurbitaceae refers to the gourd or squash family of flowering plants. These are not ferns and do not have siphonosteles. d. Dicksonia and Maiden hair fern: Dicksonia is a genus of tree ferns that may have complex vascular tissues, but not necessarily ectophloic siphonosteles. Maiden hair fern (Adiantum) was mentioned earlier and is not typically associated with ectophloic siphonosteles. Again, the correct answer is Osmunda and Equisetum, as these ferns exhibit ectophloic siphonosteles in their vascular tissue arrangement.