A synopsis of the Characeae'

42 BULLETIN OF THE TORREY BOTANICAL CLUB [Von. 91nata," having the tendency for plants to be broad above,mucroniform dactyls, reticulate oospore membrane, nodifferentiation of fertile whorls, absence of mucus, andabbreviated dactyls. Gioallenia, on the other hand, includesforms resembling the European "N. graeilis" withtendencies for plants to be narrowed above, tapereddactyls and end cells, granulate oospore membranes, formationof heads, presence of mucus.] [Three taxa whichhave mucronate dactyls, and would seem to fit here, areassigned elsewhere: N. tasmanica [Aust, Oc], N. huillensis[Af], and N. doidgeae [Af].]37a. Branchlets uniform in a whorl; homoeoclemous.38a. Gametangia never at base of whorl; antheridia140-540 p, in diameter; heads rare; monoeeious(except subsp. fiagelliformis) ..................................................................................... 1(49) Nitella furcata [cosm][includes Macrodactylae and Brachydactylae].38b. Gametangia occasionally at base of whorl; antheridialarge (to 600 1.1, in diameter) ; without heads;dioecious ............................. 2(50) Nitella duthieae [Af]38c. Gametangia never at base of whorl; antheridia 320-500 .11 in diameter; without heads, but whorlscompact, spheroid and isolated, 0.3-0.5 cm. indiameter; without mucus (4) ; dioecious .................................................................. 3(51) Nitella plumosa [Af]37b. Branchlets in a whorl of two kinds, heteroclemous; dioecious.............................................. 4(52) Nitella stephensia [Af]36b. Medium to small; dactyl end cells not mucronate (except N.pseudollabellata var. penicillata), but base of end cellabout as wide as distal end of penultimate cell, the twocell outlines tapering smoothly ............................................................................................................................ Sect. 2(14) GIOALLENIA[A few forms have somewhat mucronate dactyls, but aresmaller plants with upper whorls smaller than the lower.]39a. Oospore membrane smooth, granulate, papillate or vermiform,but not reticulate.40a. Medium to large (to 60 cm.) ; some branchlets exceeding5 cm. in length.41a. Upper whorls lax and without mucus, or rarelysomewhat spicate with mucus.42a. Medium sized (20-30 cm.) ; with or withoutcentral secondary branchlet ray ;branchlet furcations variously 2-5-furcate;rarely dioecious .............................1(53) Nitella pseudoflabellata [Af, As, Aust, Oc]42b. Medium to small (5-15 cm.) ; withoutcentral secondary branchlet ray (exceptsubsp. gracillima [As]); 1-3-furcate;monoecious or dioecious ......................................................... 2(54) Nitella gracilis [cosm][includes two pluricellulate taxa, subsp.lechleri [SA] and subsp. zeyheri [Af]].42e. Robust (to 60 cm.) ; axes 1000 la in diameter;dioecious.43a. Dactyls 2-3-celled .............................................................. 3(55) Nitella remota [Aust]43b. Dactyls (1—)2-celled .................................