_ or budding so general among Aphides. 
— Remedies. 
240 
THE DICTIONARY OF GARDENING, 
Psylla—continued. 
of plants, sucking the sap through their long beaks. 
They frequently live in company, and are often more or 
less covered with a cottony secretion. Some species give 
rise to distortions of such a kind as to cause them 
to be reckoned among gall-makers. In repose, the wings 
are sloped over the back like a penthouse, and the 
front pair are rounded at the tip. These insects may 
be known from Aphides by their rather larger size, rounded 
wings, and harder bodies, and, above all, by their power 
of leaping, which is given by the strong, thick thighs. 
They do not show the rapid vegetative reproduction 
The species are 
found on many different woody plants, and all have 
very similar habits. Several occur on the Pear-tree (see 
remarks on Insects under Pear), of which P. pyrisuga 
— 
Fic. 305. PSYLLA PYRISUGA (the Line below the Insect shows 
the natural length). 
(see Fig. 305) is probably most hurtful; and P. Mali, at 
times, does much harm to Apples. They secrete from 
their bodies a sweet, clammy substance, which is pro- 
duced at the expense of the fluids of the plants, and 
falls on and clogs the surfaces of the leaves. 
weakens the food-plants considerably. During winter, 
many of these insects are hidden in the crevices of 
the bark, or in similar shelters; hence, no such retreat 
should be permitted to exist in the neighbourhood of 
valuable trees that suffer from their attacks. 
Remove all facilities for concealment from 
the trees and shrubs. It has been recommended to wash 
the branches and leaves first with a solution of 2o0z. soft 
soap to a gallon of water, and to follow this up with 
 tobacco-water, Gishurst’s Compound, or 
. 
= 
P. t. aurea (golden). This only differs from 
colour of the 
other insecticides, as recommended under 
Aphides (which see). These may be 
pumped on to the trees from a garden 
‘PTARMICA. Included under Achil- 
lea. 
PTELEA (the ancient Greek name 
of the Elm, used from the time of 
Homer, here applied to a genus with 
similar fruit). ORD. Rutacee. A genus 
consisting of six species of hardy, un- 
armed shrubs or small trees, natives of 
temperate North America. Flowers 
greenish - yellow, cymose or corymbose, 
polygamous; calyx short, four or five- 
parted, imbricated; petals four or five, 
much longer than the calyx, imbricated. 
Leaves alternate, rarely opposite, tri- 
foliolate or pinnately five-foliolate ; leaf- 
lets ovate or oblong, pellucid-dotted, en- 
tire or serrulate. The under-mentioned 
species—probably the only one in cul- 
tivation—thrives in any common garden 
soil, and is readily increased by layers. 
the fertile ones. May and June, ł. long- 
stalked ; leaflets * or oblong, tly 
er $ 
h. 4ft. to 8ft. 
_ the in the golden-yellow 
This | 
PTELIDIUM (so named from its similarity to 
Ptelea). Syn. Seringia. ORD. Celastrineæw. A mono- 
typic genus, the species being an ornamental, stove 
shrub. It thrives best in a compost of loam, peat, and 
sand. Cuttings of the ripened wood will root readily, 
if inserted in sand, under a glass, in heat. 
P. ovatum (ovate-leaved). fl. green, minute, in axillary and ter- 
minal cymes, which are shorter than the leaves ; calyx segments 
and petals four. June. Z. opposite, coriaceous, petiolate, ovate, 
entire. h. 3ft. Madagascar, 1818. 
PTERIS. A Fern; the term is also used in Greek 
compounds to signify a wing, e.g., Pterocarpous, wing- 
fruited. 
(the old Greek name for a fern, used by 
Dioscorides, so called from pteron, a feather; in allusion 
to the shape of the fronds). Brake or Bracken. Includ- 
ing Amphiblestra, Campteria, Doryopteris, Heterophlebium, 
Litobrochia, Ornithopteris, Pesia, Pyenodoria, &c. ORD. 
Filices. A rather large, cosmopolitan genus (upwards of 
seventy species) of stove, greenhouse, or hardy ferns, in- 
eluding plants of almost. every kind of venation and divi- 
sion. Sori marginal, linear, continuous, occupying a 
slender, filiform receptacle in the axis of the involucre; 
involucre the same shape as the sorus, usually mem- 
branous, at first quite covering it, at length more or less 
spreading. Except where otherwise indicated, the under- 
mentioned species require stove treatment. -For culture, 
&e., see Ferns, 
P. albo-lineata (white-lined). A form of P. cretica. 
P. aquilina —— _Adder-spit; Common Bracken or Brake 
e 
Fern ; Eagl ern. . rhiz. wide-creeping, stout, subterraneous. 
sti. lft. or more long, strong, erect, straw or pale chestnut- 
colo fronds 2ft. to 4ft. or more long, lft. to 2ft. broad, sub- 
deltoid ; uppermost pinnz simple ; those next in order lanceolate, 
cut nearly or quite to the rachis into triangular or linear 
pinnules ; the lowest pinnz long-stalked, 1ft. or more long, with 
ample, lanceolate pinnules, the latter cut down to the rachis into 
numerous lanceolate segments, which are again fully, pinnate; — 
est entire ultimate divisions lin. long, in. broad ; rachis and 
bo s sometimes pubescent. Involucre double, or the 
