84 NEMALIONACEAE 
Cherbourg 10: 70. 1863; Schmitz, Flora 72: 438. 1889. Not 
Chantransia DC. Fl. Ег.2: 49. 1815. Not Chantransia Fr. Syst. 
Orb. Veg. 338. 1825 (at least, as to the specified types). 
Acrochaetium catenulatum sp. nov. 
Epiphytic, minute, mostly 50-150 и high; the single basal cell 
(spore) subglobose, 8-11 u in diameter; the single main axis 
suberect or ascending, 9-11 win diameter, usually 10-20 cells long, 
commonly arcuate and with a secund series of mostly simple and 
often successively shorter branches along the convex side, the 
branches beginning with the basal cell or often several cells higher, 
now and then irregularly alternate or very rarely opposite, ulti- 
mate ramuli 7-8 и in diameter; cells mostly as long as broad, 
often a little less long than broad, rarely twice as long, usually 
quadrate-orbicular in optical section, now and then discoid and 
occasionally biconcave or concavo-convex, the cell wall rather 
thick and gelatinous especially in basal and median parts, mostly 
1—2 и thick; chromatophore (2) apparently occupying nearly the 
whole cell except for a few small irregularly disposed vacuoles; 
hairs apparently wanting; monosporangia д-тти long, 5.5-7.0 M 
wide, thinner-walled than the vegetative cells, finally terminating 
the main axis and most of the branches and commonly also sessile ` 
and secund along the outer (convex) face of the arcuate-hamate 
upper half of the main axis, the emptied sporangia sometimes 
refilled by the subjacent cells, two (rarely three) successive ter- 
minal cells of axis or branch often converted into sporangia | 
simultaneously. [PLATE 31, FIGURES 12–18.] 
п Chaetomorpha cartilaginea in beach drift, La Punta, region - 
of Callao, January 25, 1907, Coker 38 p.p., associated with Acro- | 
chaetium clandestinum, Goniotrichum Cornu-cervi, С. Alsidii, 
Pleonosporium venustissimum, Erythrotrichia polymorpha, Ecto- 
carpus sp., etc. The short often flattened-globoid or even осса- 
sionally discoid cells, combined with the rather thick gelatinous | 
walls, give young unbranched plants (see FIGURE 14) some super- 
ficial resemblance to young conditions of Goniotrichum Alsidit, 
with which they are sometimes associated, but the filaments of the ` 
Acrochaetium have a less diameter and their walls are thinner. 
The cell contents are very homogeneous and the coloring matter 
the genus, has met with more or less a pt since it was revived by J. Agardh іп | 
1892. Тһе Danish species of the group have recently been monographed іп а very . 
careful and masterly fashion by Dr. L. Kolderup Rosenvinge (Kgl. Danske Vidensk- | 
Selsk. Skrift. VII. 7: 80-144. f. 18-67. 1909) 
