£96 15. Zygnema. 1. HYDROPHYTE. Pl.cell.aph. 
F. CoNjUGATiDEiE. Thallus cylindrical, threadlike, 
tubular, jointed ; coupling laterally, either by pushing out 
s. transverse tube from the middle of the joint, or by uniting 
at the angles; spore one in each joint. — Fresh-water, green. 
XV. 15. ZYGNEMA. Agardh. Zygneme . 
Thallus threadlike, simple, tubular ; jointed ; coupling 
parallelly by a short traverse tube emitted from the middle 
of each joint, through which the granules in the joints of 
one plant pass into the opposite joint of the other plant, 
and there form a single spherical spore; granules form- 
ing spots in each joint. 
1. Zygnema peclinatum . Comblike zygneme . 
Threads shining, rather longer than broad; spots two, 
oblong or 3-toothed in each joint. 
Conjugata pectinata, Voucher , 77. 
Zygnema peclinatum, Agardh Syn. 102. 
Conferva pectinata, De Candolle FI. Fr. 2,56; Engl. Hot. 1610, 
On stones, or floating in running waters. 
Tufts light green, growing blackish ; sporce spherical, 
lodged in the transverse tube, according to Agardh. 
|3. confluens. Joints as long as broad ; spots dense and 
nearly confluent. 
Conferva bipunctala, Dillw. 2. 
2. Zygnema bipunclatum. Two-dotted zygneme. 
Threads shining, twice as long as broad; spots 2, stellate. 
Conferva bipunctata, Roth Cat. 2, 204; not of Engl. Bot. 
Conferva Stellina, Muller in N. Act. Felr. 3, 93. 
Conferva cruciata, De Candolle FI. Fr. 2, 58. 
Conjugata stellina, Voucher , 75. 
Conjngata cruciata. Voucher , 76. 
Zygnema cruciatum, Agardh Syn. 102. 
Ditches and stagnant waters. 
Tufts entangled, floating ; spots starlike, radiated or 
angular. 
#. gracile. Joints three times as long as broad; spots 2, 
roundish. 
Conjugata gracilis, Voucher , 73. 
Conferva gracilis, De Candolle FI. Fr. 2, 55. 
Zygnema gracilis? Agardh Syn. 103. 
y. imipunctatum . Joints as long as broad ; spot 1, 
roundish. 
