Family Description:
Since this order contains just one family in the local area, the Cladophoraceae, the characteristics of this family are the same as those of the order. Members of the genera Chaetomorpha and Rhizoclonium have unbranched filaments, whereas members of Cladophora have branched filaments.

Species description:
Green Ball grows both along exposed coasts and in protected areas of Puget Sound, Washington. It is perennial and has isomorphic generations (sporophytes and gametophytes look similar). It generally forms small, bright green, hemipherical tufts, especially when young. Eventually, these tufts can each grow to the size of a large lime (up to 5 cm or 2 in high). In deeper water or in tidepools, sometimes Green Ball forms masses up to 7.5 cm (3 in) in diameter. The tangled filaments within the tufts trap sediment effectively, even when growing on bare rock surfaces. Often, large bubbles become trapped within the filaments as well. Sometimes the tufts of Green Ball can be found growing where all but the tips of the filaments are buried in sand or mud. When the tide goes out, water held within the tuft allows Green Ball to escape desiccation.

Within each of these tufts, the filaments are profusely branched, especially near the tips. Basally, the filaments measure up to 200 µm in diameter, but taper so that near their tips they are only 100-120 µm across. These filaments have very thick walls. Each cell has a single reticulate chloroplast, and each chloroplast contains numerous pyrenoids. Some horizontal branches also occur, especially basally in the tuft, but most branches are erect. The basal rhizoids can be either unicellular or multicellular, and either simple or branched; they attach the tuft to the rock.

At least eight species of Cladophora have been reported to occur in the northeastern Pacific Ocean; this is one of the most common. The species are difficult to identify with certainty and need to be studied to clearly define their individual character.

Source:  North Pacific Seaweeds

Synonyms and Alternate Names:
Cladophora hemisphaerica
Cladophora trichotoma