Isoetes tuckermanii

Isoetes tuckermanii (Tuckerman's quillwort)^[1] is a tetraploid species of quillwort in the Isoetaceae family. It can be found in shallow water in Newfoundland, Nova Scotia, New Brunswick, and south through the New England states to Maryland.^[2] It bears 10 to 45 long bright green to yellow green leaves that are 4 to 25 centimeters long, usually erect, but sometimes recurved. The velum covers one fourth or less of the sporangium, which is usually unspotted, 5 millimeters long, and 3 millimeters wide. The white spherical megaspores are 400 to 650 micrometers in diameter, and bear rough-crested ridges that form a hexagonal honeycomb shape. The kidney shaped microspores are 24 to 33 micrometers long, bearing tubercles.^[2] It is very similar to I. macrospora, only reliably distinguishable by cytology or through careful megaspore measurement.

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