XVI International Botanical Congess

In contrast to the biflagellated spermatozoids of most lycophytes, the sperm cell of Isoetes bolanderi is multiflagellated. Approximately 20 flagella are staggered along the length of the cell which forms a sinistral spiral of ca. 3 gyres. The two anterior-most flagella are situated over a sharp inward bend at the front of the cell. An anterior mitochondrion extends from near the cell front along one gyre and overlaps the nuclear anterior. The narrow, cylindrical nucleus tapers on both ends and coils for over two revolutions. A second elongated mitochondrion parallels the nuclear posterior and both nucleus and mitochondrion overlap a long narrow plastid that is devoid of starch. The nucleus extends just beyond the posterior mitochondrion while the plastid continues to the cell terminus. A spine of up to 44 microtubules encircles the cell periphery.