266 TEMPERATURE AND PESTS 



THE FRUIT 



others. Some species, as the American red 

 raspberry, bear gland-tipped hairs or bristles 

 on the flowering shoots. 



Temperature and pests. 



The different species of Rubus and their 

 varieties vary greatly in their relation to heat 

 and cold, and their response to these environ- 

 mental factors must always be noted. The 

 cultivated varieties of the several species of 

 Rubus seldom thrive quite so far north or so 

 far south as their wild prototypes, chiefly be- 

 cause the wild plants find natural protection 

 difficult for the cultivator to give. 



The relation of the various brambles to in- 

 sects and diseases is of rather less importance 

 to both the systematic pomologist and the 

 fruit-grower than with other plants, for the 

 reason that insects and fungi are less trouble- 

 some. But, even so, it is of importance to 

 note characteristic immunities or susceptibili- 

 ties. 



The foliage. 



The leaves of species and varieties furnish 

 characters upon which specific divisions are 

 often made. Thus the number of leaflets, the 

 size, shape, and color are all very important. 

 The leaflets of some species are smooth, ru- 

 gose, plicate, or wrinkled. The colors of the 

 upper and lower surfaces vary greatly; that 

 of the lower surface is particularly to be 

 taken into account. The pubescence on the 

 surfaces, petioles, and margins differs greatly; 

 in some species the hairs are glandular. The 

 petiole and midrib are often armed like the 

 canes. Sometimes the petiole is channeled and 

 sometimes flat. The serrations of the margins 

 are most serviceable taxonomic characters, in 

 one species, R. ladniatus, being so laciniated 

 as to give the name to the group. In other 

 species the serrations may be fine, coarse, 

 sharp, obtuse, and regular or irregular; or the 

 teeth may appear in a single or a double series. 

 These characters of the margin usually persist 

 under cultivation. 



The time at which leaves appear and their 

 color in the early spring are noteworthy, and 

 information is easily obtained in fruit planta- 

 tions. Possibly an even more important life 

 event is the fall of leaves. Some cultivated 

 species, as R. ladniatus, the cut-leaved or 

 evergreen blackberry, are almost or quite ever- 

 green. Some others of the blackberries and 

 dewberries are nearly evergreen, all such being 

 tender to cold. The Mammoth blackberry, 

 the loganberry, and their several related sorts, 

 are examples of this class. 



The flowers. 



The inflorescence is not so reliable for 

 classification as several other structures, for 

 cultivation seems to have modified the flowers 

 in many species, and hybridization has caused 

 great diversities. The inflorescence is a 

 corymb or raceme, either of which may vary 

 greatly in being long or short, dense or open, 

 in having the peduncles entire or divided, few- 



or many-flowered. Pubescences, spines, and 

 glands are almost as various as the species. 

 The cluster may be naked or covered to the 

 tip with leafy bracts. The peduncle may be 

 erect, spreading, or drooping. The length, 

 size, and color of peduncle and pedicel are 

 noteworthy, and note should be made as to 

 whether they are glabrous, pubescent, or 

 glandular. The angle the pedicel makes with 

 the axis is a fine mark of distinction; it may 

 be acute, obtuse, or at right angle. The floral 

 structures are of importance in the classifica- 

 tion of species; pomplogists, however, use 

 them but little in classifying cultivated bram- 

 bles. The date of bloom is of cultural as well 

 as of taxonomic importance and must be taken 

 into account. 



The size and color of the floral parts is 

 easily noted and very constant, therefore of 

 importance. A fine mark of distinction in 

 species and varieties is the direction of the 

 sepals after flowering. At the time of flower- 

 ing, the sepals in nearly all brambles are re- 

 versed; in some species they remain reversed 

 until the fruits mature, but in others they 

 change position, varying with the species from 

 the reversed form through all stages to clasp- 

 ing the fruit. The sepals vary greatly also in 

 different species, in size, shape, and color, and 

 may be pubescent or glabrous, glandular or 

 eglandular. 



The form of the petals is constant in species 

 of Rubus, but the color is rather variable. In 

 cultivated varieties of a species, the color may 

 vary from white to red, as is the case with 

 R. ladniatus, the cut-leaved blackberry. In 

 most of the cultivated brambles, however, the 

 color is white in all varieties. 



The relative length and color of stamens 

 and pistils, and their pubescent or glabrous 

 condition, are facts of considerable botanical 

 importance, but need seldom be considered by 

 the pomologist. The western dewberries, R. 

 vitifolius, often bear imperfect flowers, so that 

 degree of sterility in their many hybrid off- 

 spring should be noted by pomologists. In 

 hybrid brambles, the pollen is often found to 

 be shrunken or otherwise malformed. All who 

 have worked with cultivated brambles must 

 have noted in times of drought that there are 

 many sterile or practically sterile flowers. 

 Certain species and certain varieties of any 

 given species are more susceptible to this de- 

 fect than others. 



The fruit. 



Lastly, in the fruits, two characters impor- 

 tant to the pomologist are the date of ripen- 

 ing and the yield, both of which are of taxo- 

 nomic importance. All species and varieties 

 have a definite fruiting season, the beginning 

 and end of which are life events to be noted 

 in a full description of every variety. The 

 fruits of some varieties are uniform in shape 

 and size throughout the season, both matters 

 of importance but too dependent on environ- 

 ment to have much taxonomic importance. 

 Yield, also, of utmost cultural importance, is 

 too variable in accordance with climate, soil, 



