key to DeCew Guide browns

University Herbarium, UC Berkeley

CENTER FOR PHYCOLOGICAL DOCUMENTATION
DECEW'S GUIDE

KEY TO GENERA AND SPECIES OF BROWN ALGAE
	CONTENTS \| FIGURES \| ABOUT \| INDEXES: Reds · Greens · Browns \| KEYS: Browns

	1	Thallus appears filamentous	2
	1	Thallus other than a simple filament	23

<	2	Thallus wholly or partly endophytic	3
	2	Thallus free-living or epiphytic	6

<	3	Branching at right angles; multiseriate at maturity; host the epiphytic red alga Smithora	Internoretia fryeana
	3	Branching at oblique angles; uniseriate throughout	4

<	4	Lifting the surface of Hedophyllum, often erupting through the epidermis	Gononema aecidioides
	4	Filaments among the bases of the unangia in other laminarians	5

<	5	Host is Laminaria setchellii	Streblonema evagatum
	5	Host is Alaria	Streblonema pacificum

<	6	Thallus multiseriate and parenchymatous in part, though appearing filamentous	7
	6	Thallus truly filamentous in structure	8

<	7	Multseriate thallus behind a large and distinctive apical cell	Sphacelaria (see genus key)
	7	Multiseriate thallus behind an intercalary meristem that produces a uniseriate terminal filament	Stictyosiphon tortilis

<	8	Hooked branchlets unite upright branches in yarn-like strands, on fucoids	Spongonema tomentosum
	8	Branches generally free or absent	9

<	9	Reproductive organs intercalary	10
	9	Reproductive organs not intercalary	13

<	10	Minute epiphyte on Postelsia stipes; plurangia in axes and in paired, opposite branches	Pilayella gardneri
	10	On various substrates; organs in catenate series	11

<	11	Unbranched	12
	11	Branched	Pilayella littoralis

<	12	Reproductive organs large and globose, not in adjacent series	Leptonematella fasciculata
	12	Unangia in series below series of plurangia, to the tip of the filament	Pilayella tenella

<	13	Minute, epiphyte on Fucus, unangia borne laterally near filament base	Elachista fucicola
	13	On various substrates, plurangia common	14

<	14	Discoid base	15
	14	Filaments attached at the base by rhizoids or a short prostrate filament	19

<	15	Basal disc distromatic in part	16
	15	Basal disc monostromatic	17

<	16	Small (<2mm) discs on the blades of laminarians	Hecatonema primarium
	16	Circular or irregular cushions (to 10 mm), often confluent	Hecatonema streblonematoides

<	17	Short unbranched or sparingly branched uprights.	Myrionema (see genus key)
	17	Dense mat of unbranched upright filaments	18

<	18	Erect filaments 10 - 12痠 in diameter, on Nereocystis	Compsonema serpens
	18	Erect filaments 8 - 9痠 in diameter, on large algae	Compsonema fructuosum

<	19	Meristem at the base of branches, above which no lateral branching occurs	22
	19	Meristem inconspicuous and diffuse	20

<	20	Plurangia on short lateral branches, growth intercalary	Ectocarpus (see genus key)
	20	Plurangia sessile, generally asymmetrical, meristems inconspicuous	21

<	21	Plurangia arranged in unilateral series on axes	Hincksia sandriana
	21	Plurangia irregularly arranged, mostly singly	Hincksia granulosa

<	22	Plurangia irregularly conical, tapering sharply to tip	Feldmannia irregularis
	22	Plurangia cylindrical, thin, and blunt tipped	Feldmannia simplex

<	23	Thallus robust and evidently parenchymatous	24
	23	Thallus appears cylindrical, globose, saccate, or crustose	57

<	24	Thallus with distinct blades and hapteran holdfast separated by a stipe	25
	24	Thallus parenchymatous or pseudparenchymatous, stipe insubstantial or absent	44

<	25	Thallus with differentiated sporophylls and vegetative blades	26
	25	Thallus in which all blades are sporophyllous or which bear conceptacles	31

<	26	Sporophylls borne laterally on stipe, below a single vegetative blade	27
	26	Sporophylls borne otherwise	28

<	27	Teminal blade with conspicuous midrib, lamina thin, stipe flexible	Alaria (see genus key)
	27	Terminal blades smooth, lamina tough and leathery, stipe stiff and woody	Pterygophora californica

<	28	Blades formed in terminal dichotomies, without pneumatocysts	Lessoniopsis littoralis
	28	Blades with basal pneumatocysts formed laterally	29

<	29	Sporophylls and vegetative blades profuse along a flattened rachis	Egregia menziesii
	29	Blades regularly spaced on long, cylindrical branches	30

<	30	Blades and pneumatocysts small and densely packed	Sargassum muticum
	30	Blades and pneumatocysts large and well spaced	Macrocystis integrifolia

<	31	Stipe prostrate with haptera growing from sides	32
	31	Stipe upright	33

<	32	Blades branching by splitting from the base to the tip; no midrib	Dictyoneurum californicum
	32	Blades unbranched; distinct midrib	Dictyoneuropsis reticulata

<	33	Stipe branched	34
	33	Stipe unbranched, terete or flat but not blade-like	36

<	34	Stipe flattened near base; seasonally terete near tip, bearing pneumatocysts and conceptacles	35
	34	Stipe appears dichotomously and repeatedly branched near tip	Eisenia arborea

<	35	Pneumatocysts in catenate series	Cystoseira osmundacea
	35	Pneumatocysts in pairs	Cystoseira geminata

<	36	Blades with one or more midribs	37
	36	Blades without a percurrent rib	41

<	37	Blades with multiple percurrent midribs, bullations common	38
	37	Blade with a single midrib	39

<	38	Blade with five longitudinal ribs	Costaria costata
	38	Blade with three longitudinal ribs	Cymathere triplicata

<	39	Blade about as wide as long, bullate, frequently perforated	40
	39	Blade longer than wide, bullations along midrib	Pleurophycus gardneri

<	40	Stipe cylindrical, not fimbriate; blade with two basal scrolls	Agarum fimbriatum
	40	Stipe flattened, with fimbriate margins; blade base rounded or cordate	Agarum clathratum

<	41	Blades smooth, without notable bullations, ridges, or perforations	Laminaria (see genus key)
	41	Blades ornamented with bullations, ridges, or perforations	42

<	42	Stipe solid topped with a single blade	Laminaria (see genus key)
	42	Stipe hollow, several ridged blades	43

<	43	Stipe terminates in a bulbous pneumatocyst and numerous lamina	Nereocystis luetkeana
	43	Stipe narrows towards the tip and lamina	Postelsia palmaeformis

<	44	Thallus a thin blade	53
	44	Thallus coarse and strong	45

<	45	Thallus a broad blade (frequently with falcate splits), haptera arise from blade edge	Hedophyllum sessile
	45	Thallus other	46

<	46	Thallus roughly terete	47
	46	Thallus strap-like, dichotomously branched; discoid holdfast	49

<	47	Thallus unbranched or pinnately branched; strong discoid holdfast; acidulous	Desmarestia (see genus key)
	47	With numerous irregular branches	48

<	48	Arising from crustose base; branches straight or tapering	Analipus japonicus
	48	Small discoid holdfast; some branches clavate and blunt	Saundersella simplex

<	49	Thallus with a midrib and well defined terminal receptacles	50
	49	Thallus narrow, without evident midrib; receptacles poorly defined	52

<	50	Thallus with pits in parallel rows along the midrib	Hesperophycus californicus
	50	Thallus without rows of pits	51

<	51	Midrib and oval conceptacle sharply defined from blade	Fucus spiralis
	51	Midrib and elongated conceptacle grade into blade	Fucus gardneri

<	52	Dichotomies often unequal; two eggs in each oogonium	Silvetia compressa
	52	Dichotomies generally equal; one egg and a polar body in each oogonium	Pelvetiopsis limitata

<	53	Thallus epiphytic	58
	53	Growing on rocks, shells, or other inanimate substrate	54

<	54	Thallus a branched cylinder, extremely lax, lubricous, and covered with fine hairs	Haplogloia andersonii
	54	Thallus other	55

<	55	Thallus flattened	56
	55	Thallus tubular, irregular, globose, saccate, or crustose	61

<	56	Blade fan-like, splitting into more narrow blades; thallus less than five cm high	Syringoderma abyssicola
	56	Blade not fan-like, edges irregular or roughly parallel	57

<	57	Blade shape very irregular; growth from a perennial basal crust	Phaeostrophion irregulare
	57	Blades mildly flabellate but not fan-like; to twenty cm or more when mature	Dictyota binghamiae

<	58	Thallus epiphytic on Egregia	Halorhipis winstonii
	58	Thallus epiphytic on sea grasses, occasionally on algae other than Egregia	59

<	59	Medullary cells four to five times the diameter of cortical cells	Petalonia fascia
	59	Medullary cells two to three times the diameter of cortical cells	60

<	60	Thalli to 2.5 cm; margins plane	Punctaria hesperia
	60	Thalli to 20 cm; margins ruffled	Punctaria occidentalis

<	61	Thallus hollow	62
	61	Thalli crustose, not hollow	70

<	62	Thalli hollow but not distinctly tubular	65
	62	Clumps of tubular thalli found in high intertidal pools	63

<	63	Mature branches with spiral grooves creating a coiled appearance	Melanosiphon intestinalis
	63	Mature branches not spirally grooved	64

<	64	Mature branches with regular constrictions; senescent blades up to one cm wide	Scytosiphon lomentaria
	64	Mature branches without regular constrictions; seldom more than 0.4 cm wide	Scytosiphon dotyi

<	65	Irregular, sub-spherical, or globose forms	68
	65	Thalli saccate	66

<	66	Sori numerous and distinct; epiphytic solely on the red algae Neorhodomela and Odonthalia	Soranthera ulvoidea
	66	Sori not obvious; on rocks or epiphytic	67

<	67	Epiphytic on Cystoseira and other brown algae	Coilodesme californica
	67	On rocks in the low intertidal and subtidal	Coilodesme bulligera

<	68	Convoluted, globose forms; epiphytic, but often appearing saxicolous; smears when crushed	Leathesia difformis
	68	Sacs with thin but strong walls that tear but do not crush	69

<	69	Dimpled, sub-spherical sacs, commonly epiphytic	Colpomenia peregrina
	69	Finger like sacs, appear saxicolous but often epiphytic on crustose algae	Colpomenia bullosa

<	70	Crust pulvinate, rugose, and spongy; frequently spreading	Petrospongium rugosum
	70	Crust smooth and firm	71

<	71	Crustose thallus composed of tightly adherent upright filaments	Ralfsia (see genus key)
	71	Crustose thallus composed of packed but not adherent filaments	Petroderma maculiforme

copyright 2003, 2004 Paul C. Silva and the Regents of the University of California

University Herbarium, UC Berkeley

CENTER FOR PHYCOLOGICAL DOCUMENTATION DECEW'S GUIDE

KEY TO GENERA AND SPECIES OF BROWN ALGAE

copyright 2003, 2004 Paul C. Silva and the Regents of the University of California

CENTER FOR PHYCOLOGICAL DOCUMENTATION
DECEW'S GUIDE