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Document Type

Research

Abstract

The vegetative and inflorescence apices of Myosotis laxa and Mertensia virginica have been compared and contrasted in order to determine how helicoid and scorpioid cymes differ in development. The apices have been interpreted on the basis of the tunica-corpus theory, since no clear histogenic layers could be determined for these species. The stem apex enlarges and broadens at the onset of flowering, and apical dominance is lost. The number of tunica layers is reduced in both cases, and the enlargement of the apex is found to be due to more, not larger cells. The helicoid cyme of Myosotis laxa results from a continuous renewal of meristematic activity on the same side of the apex. The scorpioid cyme of Mertensia virginica develops in a stepwise fashion as a result of renewed meristematic activity at ninety degrees from the previous point of growth. Both are sympodial axes.

Publication Date

1960

Journal Title

Proceedings of the Iowa Academy of Science

Volume

67

Issue

1

First Page

76

Last Page

81

Copyright

© Copyright 1960 by the Iowa Academy of Science, Inc.

Language

EN

File Format

application/pdf

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