Fig.11. Colaclum calvum Stein, a) colony; b) rather rare temporary motile stage.
   This family is sometimes assigned to a separate order. And some college students think they invented hitch-hiking. Even very simple plants like these have been at It for millions of years.

   13b) Vegetative cells unattached and swimming by means of one or more flagella. Figs. 12 to 14.

   14a) Cells usually with green chloroplasts; if colorless an eye spot is always present, the same as in the colored species. Sexual reproduction is unknown.
Family EUGLENACEAE

   Fig.12. a), b), c), Euglena viridis,-changing forms of active cell; d) encysted cell which will live through drought or low temperatures; e) Phacus acumlnatus Stokes.
   These highly Interesting forms often become exceedingly abundant. They may be suspected by the very bright shade of green covering the pool of water.

   14b) Cells colorless and having no eye spot. Figs. 13 and 14.

   15a) Cell with a pharyngeal rod (elongated structure near base of flagelum).
Family PERANEMACEAE

   Fig.13. a) Urceolus cyclostomus Mer.; b) Entoslphon sulcatum Stein.
   Some species of the family have but one flagellum; others have two In which case one extends ahead and the other trails.

   15b) Cells without a pharyngeal rod.
Family ASTASIACEAE

   Fig.14. a) Astasla dangeardl1 Lemm.; b) Menoidium Incurvum Kleb,
   Flagellated animals of this type usually pull themselves through the water instead of carrying the flagellum behind as might be suspected.

   16a) Plants definitely cellular in structure. One or more cells. Figs. 19 to 52

   16b) Plants comparatively large, with many nuclei but with no cross-walls or definite cells. Filaments branched. Figs.15 to 18

   17a) Fresh-water species. Figs. 15 and 16.

   17b) Marine species. Figs. 17 and 18

   18a) Tubular free-living algae, somewhat branched. Sexual re­ production by non-motile eggs which are retained after fertil­ ization within the oogoniun. Both aquatic and terrestrial species.
Family VAUCHERIACEAE

   Fig.15. a) Vaucheria sessilis D.C. with reproductive organs; b) Dichotomosiphon tuberosum Ernst.
   The first species is often to be found thickly covering flowerpots, greenhouse beds or smooth damp ground in garden or field. It has been termed "green-felt".

   18b) A branching tubular thallus, parasitic within the leaves of plants of the family Araceae or the tissues of some molluks.
Family PHYLLOSIPHONACEAE

   Fig.16. Phyllosiphon arisari Kuhn. a) fila­ment; b) leaflet of Jack-in-the-pulpit with diseased spot.

   19a) Thallus without septa, the erect pinnately branched part at­ tached by a prostrate rhizome. Gametes for reproduction are produced In the pinnate branches. Along both our Atlantic and Pacific coasts.
Family BRYOPSIDACEAE