On the Pithophorace^e. 



49 



l:st degree, solitary or opposite; spores inclosed (rarely terminal), single, 

 cylindrical or subcylindrical, on an av. 106 ft thick and 375 ft long. — 

 Plate 1, figs. 1 — 3; pi. 4, fig. 1. 



[P. subvalida, filo priiicipali partis thalli cauloidese speciminum fertilium circa 

 127 fi crasso, ramos unius solum ordinis, solitaries vel binos oppositos emittente; 

 sporis inclusis (raro terminalibus), solitariis, cylindricis vel subeylindricis, c:a 10(3 ft 

 crassis et 375 fx long-is.] 



Locality. Tbis species is found by Professor D:r E. v. Martens j:r in the 

 moats outside the fortress at Palembahg in Sumatra, the 29 th of March 1862. — 

 Epiphytically on the same grows a (sterile) Ocdogonivm which has been described, 

 1. c. pag. 20, by G. V. Martens s:r under the name of Conferva (Otdogonium?) 

 Cladophorce. 



General Description. Fertile specimens. Cauloi'd part of the th alius. 

 The rather few fertile specimens I have seen of this species have had branches 

 only of the l:st degree. These have mostly occurred singly; but sometimes also 

 two and two opposite to each other. The branches are always placed a little space 

 below the top of the supporting cell. This space, however, is in general so short 

 as to be smaller than the diameter of the branch. Neither accessorial branches nor 

 helicoi'ds have been observed. The spores are, as a rule, inclosed. Only one ter- 

 minal spore I have observed, to wit, the sessile one represented in plate 1, fig. 1 st. 

 The inclosed spores are found in the principal filament as well as in the branches. 

 Their form is generally cylindric. Sometimes they are not at all swollen and then 

 they are almost perfectly cylindric (pi. 1, fig. 2); sometimes they are a little swollen 

 and are then cylindrically cask-shaped (pi. 1, fig. 3). Twin spores I have not 

 observed. 



Rh izo 'id -part of the t hall us. I have seen only one specimen, the rhizoi'd 

 part of which has not been broken off. This one quite accords as to the nature of 

 the basal cell with the specimen of P. ceqitalis nob. represented in pi. 1, fig. 6. 

 Thus a rhizoi'd part had never been developed in this specimen. 



Sterile specimens resemble the fertile ones as to the ramification. In one 

 of the examined specimens the basal part was preserved. This showed a rhizoi'd 

 part consisting of one cell (pi. 4, fig. 1 rh), parted from the cauloi'd by an oblique 

 cell-wall. 



Measurements. Fertile specimens. The vegetative cells of the principal 

 filament are on an av. 127 ,u thick; the smallest observed thickness is 105 fi and 

 the greatest 150 /i. The vegetative cells of the branches are on an av. 92 ft thick. 

 They vary between 75 and 125 ft. The length of the cells is 5 — 25 times the 

 thickness. Most frequently it is rather considerable, being 12 — 14 times the thick- 

 ness. The inclosed spores are on an av. 106 ft thick and 375 ft long. The limits 

 of variation are indicated by 21T' 'ojVs o ''■ The only terminal spore I have ob- 

 served was 75 ft thick and 555 /<. long. 



Sterile specimens. The thickness of the principal filament is on an av. 

 137 ft-, the smallest observed thickness is 11;") ft, and the greatest ISO ft. The 

 branches are on an av. 95 /» thick; the smallest observed thickness is 75 and the 

 greatest 110 ft. The length of the cells is about the same as in the fertile specimens. 



Nova Acta Reg. Soc. Sc. Ups. Ser. III. 7 



