78 
THE DICTIONARY OF GARDENING, 
Peridermium—continued. ö 
on trees under twenty years old. The peridia are about 
zin. or din. long, and Fin. high, and are usually flattened 
on the sides. They are generally crowded (see Figs. 86 
and 87), and may occur on the same branch for two or 
more years in succession; but they ultimately kill the 
branches. The Fungus is also found on the needles, in a 
form called P. acicolum. The peridia are much smaller in 
this form, and are more cylindrical, and stand in a row 
along the needles; but the latter are not so severely 
injured as the branches. The growth of the mycelium in 
Fic. 86. STEM OF YOUNG PINE ATTACKED BY PERIDERMIUM PINI. 
the branches causes the conversion of the starch and 
other food stores in the cells into turpentine and resins, 
which soak into all the tissues, and at last often appear 
on the surface of the branches. Investigations by Wolff 
and others have, of late years, led to the belief that 
this Fungus is only a stage in the life-cycle of another, 
named Coleosporium Senecionis, which has long been 
known as a widespread and abundant parasite on the 
leaves and stems of Groundsels (Senecio vulgaris and 
8. viscosus) and of Ragwort (S. Jacobea). The Coleo- 
sporium forms yellow or orange spots, crowded into 
Fig. 87. BARK OF PINUS SYLVESTRIS INVADED BY PERIDERMIUM 
Pini—a, a, Young Peridia; b, P. opened. ay 
irregular patches, or in concentric rings, or scattered 
over the leaves. These spots are composed of masses 
of small, orange-yellow spores, covered with fine warts, 
and nearly round, or cylindrical or clavate in form. Ex- 
periments in growing the Fir-parasite from these spores 
so often fail, that further evidence on their connection 
is desirable. Almost the only available remedy is to cut 
off and burn all of the trees that show the 
disease, and to keep the neighbourhood of the trees 
as clear as possible of species of Senecio, 
_ PERIGONE. The same as Perianth (which see). 
PERIGYNOUS. Petals are said to be Perigynous 
when the disk bearing them is quite free from the 
ovary, but is more or less combined with the base of 
“the calyx tube. 
PERILLA (said to be the Indian name). Syn. 
Dentidia. ORD. Labiate. A genus consisting of only 
two or three species of half-hardy, annual herbs, natives 
of the mountains of India and China. Flowers small, 
pedicellate; calyx campanulate, five-fid, nodding after 
florescence, and bilabiate; corolla tube included, limb 
shortly five-fid; whorls two-flowered, secund, disposed in 
axillary or paniculate racemes; bracts short, or rarely 
exceeding the calyx. Leaves usually violet or greenish. 
The plants thrive in any light, loamy soil, and may be 
increased by seeds. P. ocimoides crispa is sometimes 
employed in summer bedding. It requires, practically, 
little attention beyond pinching out the points occa- 
sionally, because of its very dark and distinct foliage. 
Seeds, should be sown in pans or boxes, about the 
middle of March, and placed in a gentle heat. After 
being gradually hardened off, the seedlings may be 
placed in the open border about the end of May. A 
few well-grown examples of this plant will be found 
very useful in sub-tropical gardening. 
(variable - formed). A synonym of 
P. nankinensis (Nankin). A synonym of P. ocimoides crispa. 
P. ocimoides (Ocimum-like). fl. white, numerous; corolla 
minute ; racemes shorter than the leaves. July and August. 
l. broadly ovate, 2in. to 4in. long, acuminate, cuneate at base or 
narrowed into the rather long petioles, sub-rugose, deeply crenate- 
serrate. Stem erect, lft. to 3ft. high, thick, firm, obtusely tetra- 
gonal, sulcate. India, China, &c., 1770. SYN. P. heteromorpha. 
(B. M. 2395.) : 
. . d 5 i * 
e t aad ulna Coa 
Syn. P. nankinensis. l 
PERILOMIA (from peri, around, and loma, a fringe ; 
alluding to the membranous-winged nutlets). ORD. 
Labiate. A genus comprising about eight species of 
greenhouse or half-hardy, loosely or densely branched, 
sometimes sub-scandent, leafy shrubs, natives of the 
mountains of South America, extending from Chili or 
Bolivia to Mexico. Flowers scarlet; calyx campanulate, 
slightly gibbous at back, bilabiate, with short, entire lips; 
corolla frequently pubescent or villous, with an exserted, 
incurved tube, and a short, bilabiate limb; whorls two- 
flowered, secund, axillary, or the uppermost ones sub- 
racemose. Nutlets erect, triquetrous or compressed at 
back. Leaves dentate; floral ones conformed, or the upper- 
most ones reduced to bracts. The undermentioned species 
—the only one introduced—is a very pretty half-hardy 
evergreen shrub, thriving best in a sandy-peat soil. It 
may be propagated, in April, by cuttings of young shoots, 
inserted in sand, under a glass. 
Peru, 
PERIPHANES. A synonym of Hessea (which see). 
„„ A synonym of Cantua (which 
see). 
PERIPLOCA (from peri, around, and ploke, a 
twining; in reference to the intertwining habit of some 
species). ORD. Asclepiadee. A genus comprising twelve 
species of glabrous shrubs, sometimes twining and leafy, 
sometimes erect, rigid, and aphyllous, inhabiting Southern 
Europe, temperate Asia, and tropical and sub-tropical 
Africa. Flowers often brownish or blackish within, 
greenish outside, in loose cymes. Leaves opposite, 
glabrous. The undermentioned species is a very desir- 
able plant for covering an arbour or wall, which it does 
rapidly. Any moderately good garden soil suits 
Propagated by layers or cuttings, inserted under a 
utumn. : 
glass, during summer and a 
very 
it. 
