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sporangiferous receptacle. Veins forked ; venules direct, their apices free and sporangiferous. Fronds from one 
to two feet long, pinnate, bipinnate, or tripinnate, glabrous, pilose, or squamiferous ; stipes generally ebeneous ; 
pinna} articulate with the rachis. — In habit, the species arranged under this genus, with one or two exceptions, 
vary but little from those of Cassebeera and Adiantum ; their principal 
technical distinction is the presence of a broad sporangiferous receptacle, 
with the margin of the frond slightly reflexed, and edged with a narrow 
linear indusium, which is continued, more or less, throughout every pinna 
or pinnule of the whole frond. Fig. 35 represents a portion of the frond 
of P. falcata (med. size). 
1. P. rotundifolia, J. Smith : Forster. — A pretty evergreen greenhouse 
Fern, from New Zealand. Fronds linear pinnate, one to one and a half 
foot long, reclining ; pinnae glabrous subrotund, or oblong-elliptical, 
rather obtuse, cordate at the base, coriaceous, dull green, and slightly 
crenate at the margin. Eachis and stipes densely covered with brown 
scales, lateral, adherent to a creeping rhizome. Sori linear, continuous, 
very broad; indusium veiy narrow. 
2. P. falcata, J. Smith : E. Brown. — An ornamental evergreen green- 
house species, from New Holland. Fronds lanceolate, pinnate, one to 
two feet high, rather erect ; pinnae glabrous, linear-lanceolate, oblong, 
bluntly acuminate, falcate, cordate at the base, coriaceous, and of a dull 
green. Eachis and stipes squamiferous ; lateral, adherent to a creeping 
rhizome. Sori linear, continuous, very broad ; indusium very narrow. 
3. P. Urnifolia, J. Smith: (Ptcris subverticillata, Cavanilles). — A rather 
j,y. 35. pendulous evergreen stove Fern, from Mexico. Fronds glabrous, linear, 
pinnate, one to one and a half foot long, reclining ; pinnae opposite or 
alternate, sessile, trilobed, cordate at the base, coriaceous, bluish green, with a cartilaginous margin. Sori linear- 
continuous ; indusium very narrow. Eachis and stipes purple ; stipes pubescent, terminal, adherent to a short 
scaly creeping rhizome. 
■i. P. calomelanos, J. Smith : Swartz. — A dwarf evergreen stove species, from the Cape of Good Hope. Fronds 
glabrous, deltoid, glaucous, about a foot long, bipinnate ; pinnules deltoid, coriaceous, bluish green, cordate at the 
base, sub-trilobate, with a narrow cartilaginous margin. Stipes scaly near the base, terminal, adherent to a 
short creeping rhizome. Sori linear, continued round every fertile pinnule ; indusium very narrow. 
5. P. alropurpurea, 3. Smith: Linnaeus. — An elegant dwarf evergreen frame or greenhouse species, native of 
North America. Fronds ovate-lanceolate, bipinnate, six to ten inches long ; pinnules glabrous, oblong or ovate, 
obtuse, cordate at the base, bluish green, terminal one elongate. Sori linear, continuous, forming a broad band ; 
indusium narrow. Eachis and stipes pubescent, terminal, adherent to a somewhat creeping rhizome. 
6. P. cordata, J. Smith : Cavanilles. — A very elegant soft erect-growing deciduous greenhouse Fem, from 
Mexico. Fronds delicate, bipinnate, one and a half to two feet high; pinnules ovate, cordate-sagittate, mem- 
branous, light green, and densely covered with minute hairs. Sori lineal', continuous ; indusium narrow. 
Eachis and stipes light brown ; lateral, adherent to a thick scaly creeping rhizome. 
7. P. sacjittata, T. M. : Cavanilles. — Avery pretty erect-growing warm greenhouse Fem, from South America. 
Fronds triangular, bipinnate, a foot and a half to two feet high; pinnules stalked, smooth, glaucous green, 
cordate-lanceolate, with the margins rolled under so that they become narrowly-triangular or arrow-shaped. 
Sori linear, continuous, covered by a narrow indusium. Eachis and stipes pale brown, lateral, adherent to a short 
creeping rhizome. 
8. P.fiexuosa, J. Smith : Eaulfuss. — A deciduous stove species, native of Peru and Columbia. Fronds thre^ 
or four times pinnate, and four to six feet long, somewhat twining, with alternate zig-zag pubescent branches ; 
pinnules small, ovate, glabrous, membranous, light-green, deciduous, cordate at the base, the margin cartilaginous. 
Sori linear, continuous ; indusium very small. Eachis and stipes brown, lateral, adherent to a creeping 
rhizome. 
* 
ATMOSPHEKIC ELECTEICITT. 
By Mr. J. TOWEES, C.M.H.S., &o. &c. 
FEW subjects can be of greater consequence to the cultivator than the present, inasmuch as it 
involves many, if not all, the great meteoric phenomena which govern the progress of vegetable 
growth, from that of the development of the seed-germ to the complete expansion of the full-grown tree. 
Vapours, steam or mist, dew, and the condition of the clouds, are among the most obvious of those 
phenomena. In the former article, allusion was made to some theoretic statements which are to be 
found in the Researches of Electricity, by Dr. Faraday : a few lines remain to be added, but these are 
postponed for the present, as an article just come to hand is now before me, from which some extracts 
will be given, that will tend to throw some light upon every fact derived from actual observation. 
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