TIIF. FLORA OF NF.l'.UASKA. ^ 2.3 



from what is to bo found in thoso groups, and thrii- relation to tlinni is ovident. The 

 ori^'in of the liryopliytos is also, apparently, to bo found in aljout tlio same place. 

 The elass contains l)ut one order. 



Oi-iler 20. MIAIt VCK.VK.— Till' cliaractoi-s of the class; widely distributed in 

 fii'>h and brackish water. 



SVNOl'SIS. 



Stems, branches, and loaves never corticate 1 and witlioat stipules; crown of 



carpogoue of ten cells Niti^llf<ic 



With or without cortication; stipules at the base of the leaf-whorls niorct or less 



developed; crown of live cells Clictrcac 



Family NITELLEAE. 



Crown of tho carpogono made up of two superimposed rings of live cells each; stems, 

 branches, and leaves never corticated and without stipules; leaves i)-8 in a whorl, some- 

 times with smaller accessory leaflets, with 1 3 leaflet-bearing no les; monoecious or dioe- 

 cious; carpogones single or clustered, arising from the nodes of the leaves in tho forkings 

 of the leaflets; basal coU of the carpogone usually short, covering of spore without cal- 

 careous layer. 



I. XITELLA Ao. Syst. Alg. V2X 1824. 



Monoecious or dioecious, antherids terminal on short, basal cells, only appar- 

 ently in the forks of tho leaves; carpogones single or clustered, lateral on 

 the nodes of the leaves, in monoecious species ,iust beneath tho antherids; 

 crown 10-celled; leaves with several segments, but only 1 leaflet-bearing 

 node; leaflets often repeatedly divided. 



Etymology: Latin iiiteo, shine. 



Nit«>II:i siil»sl«mi«'i'ata A. Br. Monatsbericht Berl. .-Vkad. ISriS, '^'tG. 

 yUi 11(1 (iriiminuta tiubylomcratu A. liR. of later publ. 



Plants about 15-30 cm. long, diffusely branched; stems and br.anches about 

 1 mm. in diam.; leaves only slightly less in diameter than tho stems; ver- 

 ticels of 6-8 similar leaves which are once forked, end so,'ments one-celled, 

 tapering to a sharp point; fertile verticels more or less contracted; mono- 

 ecious, fi-uctification not enveloped in .jell.y; antherids globular, 270- 

 360 ft in diam.; carpogones often clustered below the antherids; spores 

 2G0-270 /( long, nearly globular, 230 /< wide, with 5-G low spiral ridges, 

 membrane of tho mature spore very loosely reticulated <ir pitted. 



Minden, York. 



PI. XXV., Fig. 1, part of a stem with leaves, natural sizo; Fig. 2, fruiting ver- 

 ticel xoO; Fig. 3, spore x.'jO; Fig. i. membrane of a spore x3.jO. 



Aitella Ut-xili<« (L.) Ag. Syst. Alg. 121. 1824. 

 C7i«ra/f.r///.s- L. Spec. Fl. lliJT. lT5i. 



Plants rather long and not greatly branched; leaves long, 5-6 in a verticel. 

 each divided into 1-4 terminal leaflets with rounded or short-pointed 

 tips; monoecious, fructilicat ion not enveloped in .jolly; antherids l.'iO ,u in 

 diam. (Allen), carpospore about 425x375 /t (Allen), often several at a 

 node, crown evanescent. 



