Monographs Details: Xenococcus willei 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:Xenococcaceae
Description:Species Description - Cells forming extensive colonies often completely encircling the host and extending its entire length, very variable in shape and in size, decidedly angular in the juvenile stages, those destined to become gonidangia becoming rounded on approaching maturity, bright aeruginous, homogeneous; gonidangia broadly pyriform to decidedly irregular, 15-20 µ (up to 30 µ) diam.; gonidia numerous, 2.5-3 M diam.

Distribution and Ecology - Growing on Lyngbya majuscula Harvey, in a stream about five kilometers east of Coamo, no. 221 e, type; on twigs in a stream near Maricao, no. 1260.

Discussion:

PLATE 7, FIGURE 60

The nearest known relative of X. Willei apparently is X. Kernein Hansgirg, from which it differs in that it forms much more extensive colonies and in that the cells are considerably larger in all of their dimensions. This, as far as I am aware, is the second species which has been reported from fresh water.