262 



THE DICTIONARY OF GARDENING, 



Pyras continued. 



P. ussuriensis (Ussuri). /.white; filaments as long as calyx ; 

 styles three, free, slabrous. May. I. broadly oval, pointed 

 sharply toothed, fading to a fine brownish-red in autumn. Stalk 

 of roundish fruit about the same length as its diameter, h. 20ft 

 to 30ft. Amurland, &c., 1861. Tree. 



PYTHION. A synonym of Amorphophallus. 



PYTHIUM (from the Greek word pytho, I cause to 

 putrefy; plants inhabited by these Fungi soon decay). 

 A genus of Fungi, in which are included a number 

 of species, all of which are parasites in the in- 

 terior of plants. Some of them are hurtful to certain 

 cultivated plants. There is considerable doubt as to the 

 actual number of distinct species of Pythium, as several 

 are probably the same Fungus under different names; 

 e.g., the following have been described as found in 

 Potato plants : P. Equiseti (Sadeb.), P. incertum (Benny), 

 P. vexans (De By.), and P. proliferum (De By.). In 

 regard to the first three of these, Mr. W. G. Smith 

 expresses his inability to distinguish them from one 

 another. The genus belongs to a group of Fungi 

 with distinct mycelium, producing sporangia at the tips 

 of the branches, in which zoospores are produced, in the 

 form of fragments of protoplasm, each provided with two 

 cilia; or, rather, the zoospores are formed after the con- 

 tents of the sporangia flow out into the surrounding 

 water. On the mycelium, sexual reproduction is effected 

 by the formation of a globular cell (the oosphere) on 

 the end of a short branch (oogonium). Near this another 

 small branch forms, and, growing to and piercing the 

 oogonium, fertilises the oosphere, and produces thereby 

 a single resting spore or oospore within it. The very 

 nearly allied genus, Saprolegnia, differs from Pythium 

 in the zoospores being formed inside the sporangia, and 

 in more than one oospore being formed in each oogonium. 



The food or host-plants inhabited by species of 

 Pythium belong to widely-separated groups, including 

 Algaa, prothalli, and leafy plants of Equiseta, or Horse- 

 tails, prothalli of Ferns, and Potatoes. P. de Baryanum, a 

 widely-distributed parasite, lives in germinating plants of 

 Clover, Spurrey, Camelina, Maize, &c. This last species 

 renders the lowest part of the young stems soft and 

 tender, and soon causes decay. Its mycelium traverses 

 all the parts that appear withered. In damp air, branches 

 grow out, and form on the tip rounded cells, in some 

 of which are produced zoospores, in others oospores, and 

 on other branches conidia are formed. In whatever way 

 formed, the spores give origin to a mycelium, which 

 bores into suitable food-plants and reproduces the 

 Fungus. 



Remedies are hardly to be found, owing to the species 

 of Pythium being internal parasites. Diseased plants 

 should be removed and destroyed, to prevent the spread 

 of these or of any other causes of disease. 



PYXIDANTHERA (from pyxis, pyxidos, a box, and 

 anthera, an anther; the anther opening as if by a lid). 

 ORD. Diapensiaceas. A monotypic genus, closely allied to 

 Diapensia. The species is a minute, prostrate, creeping 

 herb or sub-shrub. It is a remarkably pretty little plant 

 for the rock garden, and thrives best in very sandy soil, 

 and in sunny situations. 



P. barbulata (small-bearded).* Pine-barren Beauty, fl. white or 

 rose, solitary, sessile, very numerous ; corolla flve-lobed, shortly 

 campanulate, the lobes patent and pbovate. Early summer. 

 I. imbricate, narrow, oblanceolate, entire, bearded at the base, 

 mostly alternate on the sterile branches, h. 2in. New Jersey 

 1851. (B. M. 4592.) SYN. Diapensia barbulata. 



FYXIDATE. Furnished with a lid. 



QUADRI. A term, used in Latin compounds, signi- 

 fying four ; e.g., Quadrifoliolate, when a petiole bears 

 four leaflets from the same point; Quadrijugate, in four 

 pairs. 



QUADRIA. A synonym of Gueviua (which see). 

 QUAKING GRASS. See Briza. 



QUALEA (the native name in Guiana). ORD. 

 Vochysiacece. A genus comprising about twenty-five 

 species of curious, stove, resinous trees, natives of 

 Brazil and Guiana. Flowers yellow, pink, or blue, rather 

 large, disposed in lateral and terminal racemes or 

 panicles ; sepals five, free ; petal one, unguicnlate, 

 obovate or obcordate. Leaves opposite or verticillate, 

 coriaceous, petiolate, costate ; petioles bi?landulose at 

 base. The only species in . cultivation Q. rosea 

 thrives in a compost of peat and leaf mould. Propaga- 

 tion may be effected by seeds, sown on a hotbed ; or 

 by cuttings of half-ripened shoots, inserted in sandy 

 soil, under a bell glass, in bottom heat. 

 Q. rosea (rose-coloured), fl., petal, as well as the large segment 

 of the calyx, white on the outside, rose-coloured on the inside, 

 entire ; spur shorter than the calyx. I. elliptic, acuminate, 

 glabrous on both surfaces, h. 30ft. Guiana. (A. G. 1.) SYN. 



Q. violacea (violaceous). A synonym of Q. rosea. 



QUAMASH, or CAMASH. A common name for 

 Camassia esculenta. 



QUAMOCLIT. Included under Ipomoea (which see). 

 QUAQUA (name given to the plant by the Hotten- 

 tots, who eat the stems raw). ORD. Asclepiadew. A 

 monotypic genus. The species is an erect, dwarf, 

 branched, and rather bushy, greenhouse succulent, allied 

 to Boucerosia, requiring culture similar to Stapelia 

 (which see). 



Q. hottentotorum (Hottentot), fl. in fascicles of six to ten or 

 more, along the grooves between the angles of the branches, on 

 very short pedicels ; calyx pale green or purplish ; corolla pale 

 greenish-yellow, in. in diameter, with five spreading lobes; 

 corona pale yellow, very minute. Older stems lin. thick, younger 

 ones in. to jin. thick ; angles four, rounded, armed with stout, 

 horizontal or slightly decurved, decussate, brown-pointed teeth. 

 h. 4in. to 6in. Plant greyish-green or purplish, glabrous. Nama- 

 qualand, lb?a (G. C. n. s., xii. 1.) 



QUARTINIA. A synonym of Pterolobium (which 

 see). 



QUASSIA (a name applied by Linnasus to a tree of 

 Surinam, in honour of a negro, Quassi or Coissi, who 

 employed its bark as a remedy for fever). ORD. Sima- 

 rube<K. A monotypic genus, the species being a lofty, 

 stove tree, more curious than beautiful, and in appear- 

 ance similar to the common Ash. It thrives in a com- 

 post of rich, sandy loam and leaf mould. Propagated 

 by cuttings, made of ripe shoots, and inserted in sand, 

 under a bell glass, in heat. 



ira (bitter), fl. scarlet, large, tubulose, arranged in ter- 

 minal clusters. I. alternate, impari-pinnate ; petioles winged ; 

 leaflets opposite, entire, h. 20ft. Tropical America, 1790. The 

 wood of this tree is destitute of smell, but has an intensely bitter 

 taste, on which account it was used as a tonic ; the root and the 

 bark have also been considered valuable remedies in dysentery. 

 (B. M. 497.) 



QUATERNARY, QUATERNATE. Disposed in 

 fours. 



QUEBEC OAK. See Qnercus alba. 

 QUEEN LILY. See Pluedranassa. 



QUEEN OF THE MEADOWS. See Spiraea 

 Ulmaria. 



QUEKETTIA (named in honour of the late E. J. 

 Quekett, F.L.S., an excellent botanical observer, and 

 one of our best vegetable anatomists). ORD. Orchidece. 

 A monotypic genus. The species is a singular little 

 epiphyte, of more botanical than horticultural interest. 

 It requires culture similar to Fleurotkallis (which see). 



Q. microscopies (microscopic). /. yellow, nearly sessile, cylin- 

 drical, Jin. long, disposed in a panicle about 3in. long. I. terete, 

 subulate, about 3in. long, mottled with light green, deep green, 

 and purple. Brazil. 



QUELTIA. Included under Narcissus. 

 QUERCITRON. See Quercus tinctoria. 



