词条 | Loxomataceae |
释义 | Loxomataceae plant family also spelled Loxsomataceae small family of ferns (fern) in the division Pteridophyta (the lower vascular plants (plant)). The family contains only two genera, each with a single species. Loxsoma cunninghamii grows only in northern New Zealand, whereas Loxsomopsis pearcei occurs along the Andean mountain range from Bolivia northward to Costa Rica. Both species have long-creeping rhizomes (rhizome) and highly divided leaves. The sori (fern) are enclosed in pouchlike membranous flaps of tissue (indusium (fern)) with the sporangia protruding from the mouth. Spores are globose (tetrahedral). The family is considered to be relatively primitive among the ferns and to have a relictual distribution—that is, two isolated modern species have been interpreted as the only living examples of a formerly more diverse assemblage, the presumed related species all having become extinct long ago. |
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