AND GENERAL HORTICULTURE. 



353 



PRO 



tion. It is hardy in the Southern States, and 

 is propagated by cuttings of the half-ripened 

 wood. P. pubescens, the Screw Bean or Tor- 

 nillo, and P. juliftora, the Mesquit, Algaroba, 

 or Honey-pod of the South, are both found in 

 Texas, west through New Mexico, and Arizona, 

 to tlip western foot-hills of the San Bernar- 

 dino Mountains, California. The wood of the 

 latter is very heavy, hard, and close-grained, 

 and being almost indestructible in contact 

 with the soil, is notwithstanding its crooked 

 timber, much used for railroad ties, and ex- 

 clusively for the beams and under-pinnings of 

 the adobe houses of New Mexico, etc., and 

 for posts, fencing, etc. A gum resembling 

 gum arable is yielded by this species, the 

 unripe and pulpy pods, rich in grape sugar, 

 are edible, furnishing valuable and important 

 fodder. 



Prostanthe'ra. Australian Mint-bush, or Mint- 

 tree. From prostheke, appendage, and anthera, 

 anther; connections of the anthers are 

 spurred. Nat. Ord. Labiatce. 



Green-house, evergreen shrubs from New 

 Holland, remarkable for the strong odor they 

 emit. Their flowers are produced in terminal 

 racemes, but are not of very great beauty. 

 P. rotundifolia has long been under culti- 

 vation, quite as much for rarity as for beauty. 

 Propagated by seeds or from cuttings. 



Pro'tea. From Proteus, the versatile sea-god ; 

 in allusion to the diversity of the species. Nat. 

 Ord. ProteacecB. 



A. large genus of shrubs or trees almost 

 all natives of South Africa. They are still 

 met with in large collections, and are valued 

 for the diversity of their foliage, and the 

 peculiarity of their bottle-brush-like flowers. 



Protea'ceae. A natural order of shrubs or 

 small trees, natives principally of Australia, 

 and the Cape of Good Hope. They present 

 great diversity of appearance, and are culti- 

 vated for their handsome habit and the pecu- 

 liarity of their flowers. The wood of some of 

 the Australian species is valuable for cabinet- 

 making. The order comprises forty-nine 

 genera, and about nine hundred and fifty 

 species ; well known examples are Protect, 

 Hakea, Grevillea, and Banksia. 



Prothallus. A term intended to indicate the 

 first results of the germination of the spores 

 in the higher Cryptogams. 



Protoplasm. The matter which is deposited 

 over the inside walls of a cell, subsequent to 

 the formation of the cell itself. 



Prou'stia. Named after Proust, a Spanish 

 chemist. Nat. Ord. Composite. 



A small genus of erect, or twining, warm- 

 green-house plants, natives of South America 

 and Mexico. P. pyrifolia, a very desirable 

 green-house climber, has white flower-heads 

 with round, cordate or oval leaves, densely 

 tomentose beneath. It was introduced from 

 Chili in 1865, and is increased by cuttings of 

 the half-ripened wood. 



Pruinose. Covered with glittering particles, 

 as if frosted over. 



Prune'Ua. Self-heal. Altered from Brunella; 

 derived from the German braune, a disease of 

 the throat, for which this plant was a reputed 

 remedy. Nat. Ord. Labiatce. 



A small genus of low-growing plants, com- 

 mon everywhere. P. vulgaris which has become 



PRU 



naturalized from Europe, and is common on 

 roadsides, grows about six inches high, and 

 has pale-purple flowers. P. grandiflora is a 

 handsome and vigorous plant, readily distin- 

 guished by its large flowers. There is a white 

 as well as a purple variety, both handsome 

 plants that thrive in almost any ground, but 

 prefer a shaded position. P. Pyrenaica is a 

 still larger species, with beautiful violet-pur- 

 ple flowers. 



Prunes. The dried fruit of certain varieties of 

 the Plum. 



Pruning. In pruning we remove some part 

 of a tree, shrub, or other plant, either stem, 

 branches, or roots, with a view to repress 

 growth in one direction, and direct the 

 course of the sap for the benefit of that which 

 remains. It is often quite as necessary to 

 prune trees and shrubs cultivated for their 

 flowers and foliage as those grown solely for 

 their fruit, and whether it is performed upon 

 a branch six inches through, or upon a shoot 

 so tender as to be cut by the thumb nail, the 

 object is essentially the same. The opera- 

 tion, though very simple, is one which the 

 amateur often fears to undertake ; and having 

 no confidence in his own ability, he often 



' employs some jobbing gardener, who has no 

 fears on this or /any other gardening matter. 

 Pruning is done for various ends, and unless 

 one has a definite reason for doing it, he had 

 better leave it undone. Many have an idea 

 that pruning must, for some reason, be done 

 every year; just as it used to be thought 

 necessary for people to be bled every spring, 

 whether well or ill. "We prune to control the 

 shape of a tree or shrub, and by directing the 

 growth from one part to another, obtain a 

 symmetrical form, especially in fruit trees, 

 where it is desirable that the weight of fruit 

 be equally distributed. In some trees, where 

 the fruit is borne only on the wood of the 

 previous season, the bearing portions are 

 each year removed further and further from 

 the body of the tree. In such cases a shorten- 

 ing of the growth each year will cause the 

 formation of a compact head instead of the 

 loose straggling limbs that result when this 

 is omitted. We prune to renew the vigor of 

 a plant. The inexperienced cannot under- 

 stand how cutting away a third, a half, or 

 even more of a plant can improve it in vigor 

 and fruitfulness, or abundance and size of 

 flowers. Let us suppose that a stem which 

 grew last year has twenty buds upon it. If 

 this is allowed to take its own course in the 

 spring, a few of the upper buds will push 

 with great vigor, and form strong shoots; 

 while those below will make gradually weaker 

 shoots, and for probably the lower third of 

 the stem the buds will not start at all. In 

 fruit trees, as a rule, the most vigorous growth 

 is at the top. The buds there, were the last 

 formed in the previous summer, are the most 

 excitable, and the soonest to grow the next 

 spring, and getting the start of those below 

 them, they draw the nourishment to them- 

 selves and starve the others. If, instead of 

 allowing this stem to grow at will in this 

 manner, it had been, before any of the buds 

 had started, cut back so as to leave only a few 

 of the lower ones, those having an abundance 

 of nutriment would push forth with great 

 vigor and be nearly equal in size, while the 



