AN ENCYCLOPEDIA OF HORTICULTURE. 



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 culture in almost 

 any kind of soil. Propagated by seeds, or by divisions. 



FIG. 141. RACEMOSE INFLORESCENCE OF PHYTOLACCA DECANDRA. 



P. decandra (ten-stamened).* Virginian Poke Weed ; Pigeon- 

 berry ; Red-ink Plant. /. white, in long, extra-axillary racemes, 

 succeeded, in the autumn, by dark purple berries, tilled with 

 crimson juice. /. ovate, petiolate, nearly 6in. long and about 2iin. 



broad, 

 erect, divi 



ing to purple in the autumn. Stem often purple, 

 at top. Roots large, fleshy, poisonous, h. 3ft. to 

 U)ft. 1768. A vigorous-growing plant, with a rather unpleasant 

 odour. See Fig. 141. (B. M. 931.) 



P. icosandra (twenty-stamened). JL pinkish-white, in a very 

 loose raceme, 6in. to 12in. long, attenuated at the apex. fr. de- 

 pressed at apex, watery. 1. elliptic or oblong-ovate, acuminate, 

 mucronate, rather thick, 4in. to 9in. long (including the slender 

 petiole of lin. to 3in.). and liin. to 4in. broad, but sometimes as 

 much as 1ft. 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,. 



FHYTOLACCACEJE. 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 unisexual, 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 aestivation, 

 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 



Phytolaccacese 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 Chenopodiacece, contains nineteen genera and about 

 sixty species. Examples: Petiveria, Phytolacca, and 

 Rivina. 



PHYTOMYZA. A genus of small, two-winged flies, 

 the larvae 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 

 *in. in spread of wing, and Ain. 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 pupae, 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 larvae 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 

 larvae 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 larvae. 



PHYTON. A plant. "A rudimentary plant, out of 

 numbers of which perfect plants are made up " (Gaudi- 

 chaud). 



PHYTOPHTHOH.A (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 conidinm (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. infestan*), 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, &o. 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 



