Algae1_all-split2_Page_010

29- Thalli erect, transversely zonate, often irridescent blue
in the water; colorless medulla two cells thick; about
8 to 14 cortical cells over each medullary cell or
each surface ------- Zonaria crenata
29- Thalli prostrate, longitudinally striate, bright orange
to dull brown in the water; the upper surface with
the same number of cells as the lower surface
often, over each medullary cell as the lower surface;
medullary cells thick ----- Zonaria variegata
30- Intertidal, usually - dense tufts, cells up to
twice as long as broad, hook-like or short
lateral branches present; plurilocular organs
about _ as long as broad --- Ectocarpus breviarticulatus
30- Subtidal, not densely tufted, cells becoming
longer than twice their diameter, without hook-like
or many lateral branches; plurilocular organs
more than twice as long as broad ------- 21
31- Plurilocular organs oblong - cylindrical; thalli on rocks
or epiphytic, generally over 1 cm. tall --- Ectocarpus indicus
31- Plurilocular organs pyriform to lanceolate; epiphytic,
less than 1cm tall -------- Ectocarpus padinae
32- Propagulae with 2 cylindrical arms; branching with a
unilateral tendency; usually epiphytic --- Sphacelaria furcigera
32- Propagulae with only 2 knobs; branching dichotomous to
irregularly pinnate; thalli usually on inorganic substrata --- 33