or THE DESMIDIEJi. 



745 



with others above, or with whorls of knot-like projections, ends abruptly 

 truncate. Endochrome with a terminal rounded clear space at each end, in 

 which are active granules. 



D. davatum (Kg.). — Frond slender ^ 

 suture scarcely prominent, segments 

 eight or ten times as long as broad, 

 slightly clavate near the ends, and ulti- 

 mately somewhat attenuated, basal infla- 

 tion sometimes solitary, sometimes hav- 

 ing another slight one above it ; ends 



verrucosum (Bailey). — 

 stout, suture forming- a 



DOCLDIUM 



Frond rather 



rim; seg-ments five or six times longer 



undulations due to so many whorls of 

 small tubercle-like prominences j ends 

 entire. U.S.A. 



D. nodosum (Bailey). — Frond stout, 

 sutm'e forming a rim ; segments three or 

 four times as long as broad, "v%dth four 

 j)ro7m'nent injlated nodes, includifiy the 

 basal, which is somewhat the largest, 

 and which are due to so many whorls of 

 knot-like prominences or large tubercles ; 

 ends entire ; e. v. crenate. U.S.A. 



D. coronatum (Breb.). — Frond stout, 

 suture forming a thickened projecting 

 rim ; segments fom' to six times as long 

 as broad, tapering, regularly inflated up- 

 wards from the base, so as to produce 

 an undulated margin, the basal inflation 

 the most prominent, the others less so, 

 and wanting towards the ends ; ends 

 bordered by prominent tubercles, projeetiny 

 all round; e. v. circular, bordered by the 

 tubercles ; e. f coai'sely punctate. F. 



D. undulatum (Bailey). — Frond slender, 

 suture foiTuing a minute rim, segments 

 eight to ten times as long as broad, 

 with six or eight sinuations at regular in- 

 tervals, producing as many inflations 

 besides the basal, which is not larger 

 than the others ; ends and bases crenate. 

 U.S.A. 



D. JE7irenbergii(Ralfs). — Frond slender, 

 linear; sutiu'e forming a very shai'ply- 

 defined rim; segments eight to twelve 

 times longer than broad, basal injlation 

 having another smaller one above it, sides 

 otherwise straight, ^ara//^'/; ends crenate, 

 owing to a nimiber of emarginations 

 from the edge of the truncate extremi- 

 ties, from three to five of the crena- 

 tm'es being usually visible ; e. f. punc- 

 tate, or rough with minute granules. 

 Sporangium suborbicular or elliptic, or 

 slightly angular, smooth, placed between 

 the deciduous empty fronds. Ciliated 

 zoospores formed by segmentation of the 

 cell-contents, and their emission effected 

 through the opened apex of each of one, 

 two, or three specially-formed lateral 

 tubes arising from beneath the base of 

 one of the segments (vide supra, p. 716 ; 

 m.46,47). L. 1-71" to 1-59"; B. 1-1111" 

 to 1-961". (n. 8 .t 11.) = Pleurotmiium 

 MrenberghUmeB&Yv). G.B., I., R, G., 

 U.S.A. 



entire; e. f punctate. L. 1-65" ; B. 1-813". 

 (ii. 9.) = Pleurotcenium davatum (De 

 Baiy). G.B., I., F., G., U.S.A. 



D. nodulosum (Breb.). — Frond vei-y 

 stout, the thickened suture forming a 

 projecting rim ; segments fom' to six 

 times as long as broad, scarcely atte- 

 nuated, regularly injlated at intervals so 

 as to produce an undulated margin, the 

 basal inflation the most prominent, the 

 others as they approach the ends less so, 

 where they are indistinct or wanting; 

 ends entire ; e. f. coarselv punctate. L. 

 1-50"; B. 1-428". =I>. crenulatum (Ehr.), 

 Pleurotcenium nodulosum (De Bary). 

 G.B., I., F., G., U.S.A. 



D. truncatum (Breb.). — Frond stout, 

 the thickened sutm-e forming a rim ; seg- 

 ments three or fom' times longer than 

 broad, tapering, basal inflation solitary, 

 sides othericise gradually curved ; ends en- 

 tire; e. f -punctsite.^ Pleurotcenitwi trun- 

 catum (Nag., De B.). L. 1-81" to 1-72" ; 

 B. 1-527" to ]-429". G.B., I., F., G. 



D. co?istrictu?n (Bailey). — Frond stout, 

 suture not prominent ; segments five or 

 six times longer than broad, not at- 

 tenuated, with four distinct eqiddistant 

 sitiuations producing four equal gently 

 curving prominences besides the basal 

 inflation; ends entire. U.S.A. 



D. Baculuni (Breb.). — Frond slender, 

 suture not prominent ; segments very 

 many times longer than broad, basal 

 inflation very conspicuous, solitary, sides 

 otherwise straight, \qyy nearly parallel, 

 large granules of the "^endochrome in a 

 single series ; ends entire ; e. f without 

 puncta. L. 1-111" ; B. 1-1937". (iii. 38.) 

 = Pleurotcenium Baculum (De Barv). 

 G.B., F., G., U.S.A. 



D. minutum (Balfs). — Frond slender, 

 suture not prominent ; segments four to 

 six times longer than broad, somewhat 

 tapering, injlation obsolete, sides straight^ 

 ends entire ; e. f without puncta. L. 

 1-212"; B. 1-1582". = Penium Ralfsii 

 (De Bary). G.B., I., F., G., U.S.A. 



D. hirsutu7n (Bailey). — Frond rather 

 slender, sutiu'e not prominent, segments 

 four to six times as long as broad. 



