XI TELL A. 95 



NITELLE.E. 



LEONHARDI in Lotos, XIII, p. 69 (1863). 

 Charge epigijnde BKAUN in Ann. Sc. Nat. ser. 2, 1, p. 350 

 (1834). 



Stem and branchlets entirely without cortex. 

 Branches normally two or more at a stem-node. 

 Fertile branchlets normally furcate.* Ultimate rayst 

 one or more-celled, other rays one-celled. Coronula 

 of oogonium of 10 cells in two tiers of 5. 



Genus 1. NITELLA Agardh (emend. Leonhardi). 



Nittlla AGARDH Syst. Alg. p. xxvii (1824) pro parie. 

 LEONHARDI in Lotos, XIII, p. 69 (1863). 

 BRAUN in Cohn, Krypt. Fl. Scliles. I, p. 395 (1876). 



Nitella sect, furcatx BRAUN in N. Denks. Schweiz. Ges. Xaturw. X, 

 p. 6 (1849). 



Nitella sub. gen. Eunitella BRAUN in Hooker's Journ. Bot. I, p. 194 



(1849). 



Nitella sect, ebracteatse WALLMAN Forsok Syst. Charac. pp. 12 &. 15 

 (1853) ; Transl. pp. 11 & 14 (1856). 



Branches normally two at a stem-node. Fertile 

 branchlets simply or repeatedly furcate, with more or 

 less equal rays, or rarely simple with a single node. 

 Antheridia terminal, situated in the furcations of the 

 branchlets. Oogonia produced laterally at the nodes 

 of the branchlets, in the monoecious species below the 

 antheridia. Oospores ellipsoidal or spheroidal, laterally 

 compressed. 



A large genus, presenting a wide range as regards 

 facies and complexity of vegetative structure, varying 



* As a matter of convenience, we vise the terms furcate and furcation in 

 connexion with each point of division of a branchlet in the Nitellese, though 

 strictly speaking it is applicable only to those divisions in Nitella where 

 an antheridium is produced ; in other cases all but one of the limbs are 

 lateral. This point is well exemplified by Filarszky-Nandor in the diagram- 

 matic plate (t. 3) of his Die Characeen Ungarn (1893). 



f We use the term ray for each limb of the branchlet of a Nitella or 

 Tolypella, whether central or lateral; the primary ray denoting the simple 

 basal portion (stalk) of the branchlet, the secondary rays those limbs which 

 arise at the first node, and so on in the case of further furcation, but the 

 limbs arising at the uppermost furcation are also styled ultimate rays. 



