| Description: |
Gametophyte thallus reddish brown, brownish, grey brown or olive green in the field, drying to brownish purple, attached by a minute but stout holdfast; stipe indistinct; blade orbiculate to elongate, auriculate and/or cucullate; base slightly to extremely cordate, overlapping to appear umbilicate; margins sometimes much pleated; blades single or multiple, sometimes forming a rosette. Thallus monostromatic, 58–70 µm thick with cells in surface view 8–16 × 6–8 µm and in transverse section 30–34 × 9–10 µm. Usually dioecious; sori marginal; male gametangia in packets of 4 × 4 in surface view and ×8 in transverse section ( = 128 gametes); zygotosporangia in packets of 2 × 4 in surface view and ×2 in transverse section ( = 16 zygotospores). Neutral sporangia are sometimes present. |
Species:
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Porphyra umbilicalis (Linnaeus) Kützing |
