EVERYDAY SCIENCE

Detailed explanation-1: -Siphonostele-A stele in which the vascular tissue is in the form of a cylinder surrounding the pith, as in the stems of most ferns and other seedless vascular plants. Solenostele-A type of siphonostele, in which the vascular tissue in the stem forms a central cylinder around a pith, with widely spaced leaf gaps.

Detailed explanation-2: -Dictyostele-if multiple gaps in the vascular cylinder exist in any one transverse section. The numerous leaf gaps and leaf traces give a dictyostele the appearance of many isolated islands of xylem surrounded by phloem. Each of the apparently isolated units of a dictyostele can be called a meristele.

Detailed explanation-3: -2 The term solenostele is being used in the strict sense intended by Gwynne-Vaughan (1901) to denote an am-phiphloic siphonostele without overlapping leaf gaps, whereas dictyostele refers to an amphiphloic siphono-stele with overlapping leaf gaps, as proposed by Brebner (1902).

Detailed explanation-4: -Siphonostele is a protostele or medullated protostele with a nonvascular pith in the center that lacks leaf gaps.

Detailed explanation-5: -The correct answer is Solenostele.