Aglaothamnion cordatum (Borgesen) Feldm.-Maz.
Ph.D. 459 (1941)
Conservation Code:
Not threatened
Naturalised Status: Native to Western Australia
Name Status:
Current
Scientific Description
John Huisman & Cheryl Parker,
Monday 20 June 2011
Habit and structure. Thallus generally small, to 15 mm in height, filamentous, uncorticated, alternately branched with a single lateral branch per axial cell, attached by a cluster of rhizoidal cells. Lower cells of primary axes 100–140 µm in diameter, often with L/B ± 1 but sometimes more elongate. Mid thallus cells 140–180 µm long by 50–80 µm in diameter, tapering to upper elongate cells 7–10 µm in diameter, occasionally with terminal hairs.
Reproduction.
Spermatangia arising on spermatangial mother cells that arise
secundly on lateral branch cells. These are borne in series of 2–3 cells that
then divide longitudinally once and then transversely once, such that the
resulting cluster of four cells looks cruciate when viewed from above. Each of
these four cells produces a cluster of spermatangia that are clavate,
approximately 7 µm long and 3–4 µm in diameter. Carpogonial
branches 4-celled, arising on a supporting cell borne laterally on an axial
cell. A second cell is produced opposite the supporting cell and this functions
as an auxiliary mother cell. Auxiliary cells arising from both the
supporting cells and the auxiliary mother cell. Gonimolobes cordate,
composed entirely of carposporangia 18–19 µm in diameter.
Carposporophytes with two opposite gonimolobes, in total to 350–370
µm broad. Tetrasporangia borne on distal region of lateral branch
cells, ellipsoidal, 40–45 x 30–35 µm, tetrahedrally divided, generally
borne singly but often with a sporangial initial proximal to the mature
sporangium.
Distribution.
Widely distributed in warmer waters.
