AN ENCYCLOPADIA 
OF HORTICULTURE. 119 
Phytolacca—continued. 
of the perianth. Fruit sometimes deep purple, depresso- 
globose, succulent ; carpels five to twelve, free or connate. 
Leaves alternate, sessile or stalked, acute or obtuse, 
entire ; stipules none. The under-mentioned species—those 
best known to cultivation—are very desirable, hardy, 
herbaceous plants. They are of easy c e in almost 
any kind of soil. Propagated by seeds, or by divisions. 
ip 05 
22 
FIG, 141. RACEMOSE INFLORESCENCE OF PHYTOLACCA DECANDRA. 
P. decandra (ten-stamened).* Virginian Poke Weed; Pigeon- 
berry ; Red-ink Plant. i. white, in long, extra-axillary racemes, 
succeeded, in the autumn, by dark poms berries, filled with 
crimson juice. l. ovate, petiolate, nearly 6in. long and about 24in, 
broad, changing to purple in the autumn. Stem often purple, 
erect, divided at top. Roots large, fleshy, poisonous. B. 3ft. to 
10ft. 1768. A vigoroumgrowing plant, with a rather unpleasant 
odour, See Fig. 141. (B. M. 931.) 
P. icosandra (twenty-stamened). jl. pinkish-white, in a very 
1008 raceme, bin. to 12in. long, attenuated at the apex. fr. de- 
pressed at apex, watery. l. elliptic or oblong-ovate, acuminate, 
< mucronate, rather thick, ain. to 9in. long (including the slender 
petiole of lin. to 3in.), and 14in. to din. broad, but sometimes as 
much as lft. long. Stem 2ft. to 3ft. or more high. Mexico, &c. 
(B. M. 2633, 4967.) Syn. P. mexicana (S. B. F. G. 571). 
P. mexicana (Mexican). A synonym of P. icosandra. 
PHYTOLACCACEÆ. A natural order of trees, 
shrubs, or herbs, with a woody base, usually glabrous; 
they are mostly tropical and sub-tropical, but a few are 
found in temperate regions. Flowers often greenish or 
white, hermaphrodite or unisexnal, generally racemose, 
rarely axillary, very often bracteate and bibracteolate ; 
perianth herbaceous or coriaceous, rarely membranous or 
coloured, four or five-parted, very rarely obconical and 
disk-formed, with the segments imbricated in æstivation, 
fruit-bearing ones persistent; petals (except in one 
species) wanting; stamens four or many, rarely peri- 
gynous, often inserted on a hypogynous disk; filaments | 
filiform or subulate, free or connate at base, generally 
persistent; racemes terminal and axillary. Fruit of one 
Phytolaccacez — continued. 
or more carpels. Leaves alternate, entire; stipules none, 
or small, or reduced to tubercles. Several species of 
Phytolacca have economic properties, mostly acrid, vesi- 
cant, or drastic. The order, which was long confounded 
with Chenopodiacew, contains nineteen genera and about 
sixty species. Examples: Petiveria, Phytolacca, and 
Rivina. 9 
PHYTOMYZA. A genus of small, two-winged flies, 
the larve of which mine or burrow between the surfaces 
of the leaves of many plants, both wild and cultivated. 
Among the latter may be mentioned Turnips, Wallflowers, 
and Peas; in fact, most low garden plants, and various 
shrubs and trees, are liable to attack. The species of 
this genus are numerous, but all are of small size, about 
šin. in spread of wing, and min. long. They are not un- 
like very small house-flies in form, and are usually dark, 
slaty-black, or ash-coloured, with the head and the legs 
often paler, The maggots are whitish; they tunnel out 
a winding gallery, which may not be visible on the upper 
surface of the leaf. When full-fed, they change, in the 
leaf, into chestnut, barrel-shaped pup», deeply ringed, 
and showing no external sign of the insect’s form. The 
flies emerge in May and June. One of the most 
destructive and widespread species is P. nigricornis, 
the larve of which live in many different plants. See 
also Holly-leaf Fly. Fortunately, the mines, unless 
very numerous, do no great harm to the plants in whose 
leaves they are formed; but the unsightly blotches on 
choice garden plants may render the destruction of the 
larvæ desirable. This can be accomplished by crushing 
the mine, and the contained larva or pupa, between the 
finger and thumb; or the leaves may be picked off, and 
burned. Owing to the mode of life, external applications 
are of no avail in reaching the larvæ. 
PHYTON. A plant. “A rudimentary plant, out of 
numbers of which perfect plants are made up” (Gaudi- 
chaud). 
PHYTOPHTHORA (from the Greek phyton, plant, 
and phthora, destruction). A small group of parasitic 
Fungi, very closely allied to Peronospora in all important 
points of structure (see Peronospora), except that the 
stems bearing conidia (conidiophores) do not, as in that 
genus, produce only a single conidium on the tip of each 
branchlet. Instead of this, after a conidium is formed 
at the tip, the branch grows on from just below it, and 
produces a new conidium (see Fig. 142); and this process 
may be repeated several times. The reproduction by 
zoospores formed in the conidia, and also by oospores, 
or “resting spores,” is much like that of Peronospora 
nivea. Few species are known, but of these one is the 
dreaded Potato-disease Fungus (P. infestans), too often 
seen wherever Potatoes are cultivated. Another is 
P. Fagi (also called P. omnivora), the cause of very 
widespread and serious disease in Beech seedlings, in 
many parts of Europe. It also grows well in seedlings 
of most of the commonly - cultivated coniferous trees, 
in the commoner Maples, and in many low-growing plants, 
e.g., Sempervivum, Clarkia, &. This latter Fungus has 
not yet caused damage in Britain; but, from its wide 
distribution, and its hurtfulness abroad, there is reason 
to dread its ravages should it appear in these islands. 
A short notice of it will, therefore, not be out of place 
here. It is injurious to trees only in the seedling stage, 
but, when it breaks out in a bed of seedlings of the 
kinds named above, the disease makes very rapid pro- 
gress around the centres of infection. This progress is 
more rapid in warm, damp weather, and in shady situa- 
tions, and, most of all, in beds crowded with young 
plants. 
In the Beech, in which the disease has been most fully 
studied, the seedlings become black, and perish almost 
before germination; or they form the seed leaves and 
