490 PLAGIOCHILA. 
amplexicaulia, apice subtruncato breviter paucispina, margine antico 
concavo integerrima vel 1—2-denticulata, postico distanter dentato- 
serrata, dentibus omnibus 10-12; cellulee mediocres subconformes 
vix oblongate, pariete ad angulos parum incrassato. 
Flores utriusque sexus desunt. 
52, PLAGIOCHILA DICHOTOMA (Web.) 
Prodr. p. 133 (sub Jungermania); Lindenb. Sp. Hep. t. 13 et 17 ; 
G. L. et N. Syn. Hep. p. 35. 
Hab. Ad ramulos in sylvis ripariis humidis juxta flumen Amazonum, 
precipue ad pedem Andium orientalium secus fluvios Pastasa, Bom- 
bonasa, &e. Advyenit etiam e Brasilia australiore, insula Trinidad 
aliisque Antillis, Africa et India tropicis. 
F 2°75 x 1°63, 2°0x ‘9; ¢ ds; per 3:0 x°1:5™™. 
Caudex repens ramosus, caules subhorizontales 1-3-pollicares, flabelli- 
formi-divisi, ex parte pinnati, ex parte dichotom, raro fasciculato- 
ramosi. 
Folia pallide viridia vel fulva, dissita vel subcontigua, vix unquam 
imbricata, caulina obovato- (rarius ovato-) oblonga, apice rotundato—- 
raro etiam margine postico supra medium—spinuloso-dentata den- 
ticulatave, utroque margine basi subrecurva, antice decurrentia, 
dentibus 8-16, brevibus ; folia ramea angustiora, rhomboidea vel 
ligulato-oblonga, apice paucidenticulata raro solummodo repanda 
retusave ; cellulee mediocres suboblongee. 
Flores Q terminales, seepe dichotomiales; innovatione autem interdum 
unilaterali nullave. Bracteze foliis submajores, 1-jugze, toto margine 
subspinoso-dentate, perianthio appressee vel subdissite. 
Perianthia subemersa oblongo-campanulata, antice subspinoso-alata ore 
rotundato bilabiato spinosa. 
Var. patentissima (= P|. patentissima Lindenb. Sp. Hep. 64, t. 12). Viri- 
dior, seepe sublurida, magis robusta, foliis minus dentatis, perianthiis 
exalatis—Ad fluminis Amazonum afiluentes inferiores, Trambetas, 
Aripecuru, Ramos, &c. arborum radices ramosque inundatos in- 
vestiens. 
Var. fluitans 8. Caules 4-12-pollicares, foliosi, iteratim dichotomi, angulo 
furearum acuto. Folia imbricata, latiora, flavido-olivacea, omnia 
subrhomboidea, apice rotundato, truncato retusove integerrima, raro 
repando-undulata.x—Ad ramulos fluvii Casiquiari inundatos, socio 
Hydropogonte fontinaloide (Hook.) Brid., fluitans.—Forsan species 
propria = Pl. fluitans Mst. 
Var. rivicola S. Planta ¢. Caules ascendentes 2-3-pollicares, pinnati, 
ramis paucis longis simplicibus, rarius bilidis. Folia fulva tenuia 
latiuscule imbricata (2°5 x 1:6, 1-7 x 1:1™™) oblique oblonga ovatove- 
oblonga, apice rotundato pauci-denticulata, basi antica longe oblique 
decurrentia ; cellule »™" diametro, eequilatero-hexagone pellucide. 
Andrecia terminalia tenuispica.n—Ad rivuli saxa juxta Tavalosos 
Andium Peruvie. Planta mascula Pl. dichotome videtur, licet pin- 
nata nec dichotoma ; distat insuper a typo foliis magis imbricatis 
oblongis, nunquam nec obovatis nec rhomboideis. 
Obs. I have examined what purported to be an original specimen of 
Swartz’s Jung. patula, from Jamaica, which is exactly what I have con- 
sidered typical “ dichotoma.” It is very different indeed from the “ Plag. 
