136 THE NURSERY-BOOK. 



Biota. See Thuya. 



Biotia. See Madia. 



Bird of Paradise Flower. See Strelitzia. 



Bird's-tongue Flower. See Strelitzia. 



Birch. See Betula. 



Birthwort. See Aristolochia. 



Bitter Sweet. See Celastrus and Solanum. 



Bitter Vetch. See Orobus. 



Bivonaea. Crutiferce. 



Increased by seeds, which should be sown in spring where 



the plants are intended to remain. They should be thinned 



out to insure full growth. 



Bixa (Arnatto). Bixinece. 



Propagated by seeds sown when ripe, in bottom heat, or 

 by cuttings put in sand under a hand-glass, in heat ; the 

 latter is the better method. 



Blackberry (Rubus villosus and vars.). Rosacece. 



New varieties are obtained from seeds, which may be sown 

 as soon as they are cleaned from the ripe fruit, or which may 

 be stratified until the next spring. If the soil is in prime con- 

 dition, fall sowing is preferable. 



Varieties are multiplied by suckers and by root cuttings. 

 The suckers spring up freely about the old plants, especially 

 if the roots are broken by the cultivator ; but they have few 

 fibrous roots and are inferior. The best plants are obtained 

 from root cuttings. Roots from one-fourth to three-eighths 

 inch in diameter are selected for this purpose. The roots 

 are dug in the fall, cut into pieces an inch or two long, and 

 stored until early spring. They may be buried in boxes of 

 sand after the manner of stratified seeds, or stored in a cool 

 cellar ; callusing proceeds most rapidly in a cellar. The 

 pieces are planted horizontally an inch or two deep, in loose, 

 rich soil. It is best to put Ihem in a frame and give them 

 slight bottom heat, although they will grow if planted in the 

 open in April or May, but the plants will make much less 

 growth the first season. Some varieties do not strike quickly 

 without bottom heat. When the variety is scarce, shorter 

 and slenderer pieces of root may be used, but these demand 

 bottom heat. The heat in the frames is usually supplied by 

 manure, or the heat of the sun under the glass may be suffi- 

 cient. In these frames the cuttings can be started in the 

 north late in March, or some six or eight weeks before the 



