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Open Access Thesis

Keywords

Onagraceae; Onagraceae;

Abstract

Twenty-two species of Onagraceae in 6 genera occur in Iowa. Habitat data, flowering times, frequency, and geographical distributions were determined from field observations and herbaria records. Taxonomic keys and descriptions of the twenty-two species are also included. Although most species were clearly differentiated, two areas of taxonomic confusion existed in the family. Morphological differences were found to exist between three species commonly confused in previous flora studies: Oenothera biennis L. ssp. centralis Munz; O. strigosa {Rydb.) Mack. & Bush ssp. canovirens (Steele) Munz; and O. parviflora L. O. parviflora is reliably separated from the other two species by its subterminal sepal-tip appendages which are separate during bud formation, while O. biennis ssp. central is and O. strigosa ssp. canovirens have terminal sepal-tip appendages which are closely connivent before anthesis. O. biennis ssp. central is and O. strigosa ssp. canovirens are most easily separated by the differences in pubescence of the calyx and capsule. O. biennis ssp. centralis has a sparse, erect pubescence (>1 mm), usually with short, appressed hairs {<.2 mm), while O. strigosa ssp. canovirens has sparse to dense, ascending hairs (>1 mm) with short, appressed hairs (<.2 mm). Epilobium coloratum Biehler and E. adenocaulon Haussk. differ significantly in seed markings, seed shape, coma color, and pubescence on the stems of the inflorescence. E. coloratum has papillose seeds that are rounded distally with a coma that is brown at maturity. The pubescence on the stems of the inflorescence consists of small, incurved hairs (<.3 mm) found only on the angles. The seeds of E. adenocaulon are striated and have a short, distal beak with a coma that is white at maturity. The pubescence on the stems of the inflorescence is composed of spreading hairs (>1 mm), as well as smaller incurved hairs (<.3 mm) found on both the angles and the sides. E. adenocaulon has a flowering peak that occurs 2 to 3 weeks before that of E. coloratum. 0. strigosa ssp. canovirens appears to be widely distributed across the state, whereas 0. biennis ssp. centralis is restricted to eastern Iowa. 0. parviflora is rare (4 collections) and has been collected only in the north central and northeastern sections of the state. E. coloratum is common across the state except in the extreme western tier of counties. E. adenocaulon occurs infrequently across the northern half of the state except in the extreme northwestern corner of the state from which there are no collections.

Year of Submission

1980

Degree Name

Master of Arts

Department

Department of Biology

First Advisor

Lawrence Eilers

Second Advisor

Daryl Smith

Third Advisor

Nixon Wilson

Comments

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Date Original

1980

Object Description

1 PDF file (77 leaves)

Language

en

File Format

application/pdf

Included in

Biology Commons

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