Monographs Details: Stigonema cornutum N.L.Gardner
Authority: Gardner, Nathaniel L. 1927. New Myxophyceae from Porto Rico. Mem. New York Bot. Gard. 7: 1-144. pl. 1-23.
Family:Stigonemataceae
Description:Species Description - Filaments very irregular in shape and size, the main part usually very blunt, 25-30 µ (up to 50 µ) diam.; branches of two sorts, one similar to the main frond, sparse, arising without any order, deeply constricted at the base, later completely separated at the constricted base from the parent frond; the other more numerous, arising in a similar manner, smaller, bearing a long, sharp, usually curved, hyaline apex, changing to amber color after the hormogonia disappear, the latter may or may not be deciduous; cells 4-6-seriate, 8-12 µ diam.; heterocysts small, rather sparse; sheath homogeneous, hyaline, changing to slightly yellowish when old.

Distribution and Ecology - Growing on soil along the road towards Monte Montoro, Maricao, no. 1077, type; on moss, fern roots, etc., between Aibonito and Cayey, no. 1975.

Discussion:

PLATE 21, FIGURE 53

The cornute habit of Stigonema cornutum reminds one of Kuetzing's Stigonema polyceras (1851, pl. 38) in which the attenuated portion contained cells. It was learned later that Kuetzing's plant is a lichen. The attenuated portion of the branches in the above species consists of homogeneous, hyaline tegument, and the plant is a typical Stigonema. The cells in no. 1290 are larger than those of the type and more regularly arranged in nodes.