CULTURAL DIRECTIONS 
353 
blanched heads without tying'. Express Cos and Paris 
White Cos are good examples of the first, and P>ath Cos 
of the loose-closing varieties. 
“The butter and crisp classes are separated alike into 
cabbage-heading and bunching, the former referring to 
plants whose leaves overlap one another in such a 
smooth, regular way as to form a head like a cabbage, 
and the latter to those whose heads are open, clustered, 
or bunched in arrangement, or if overlapping one another 
at all doing so at the heart only, all the outer or visible 
portions remaining more or less loose leaved. Hanson 
and I’ig Boston are good examples of the cabbage-head- 
ing varieties, and Early Curled Simpson, Prize Head and 
Lancaster of the bunching varieties. Under the latter 
subclass are embraced all degrees of clustered growth 
from varieties loose-leaved, like an endive, and repre- 
sented by Boston Curled and Green Fringed, to those 
densely bunched and represented by Black-Seeded Simp- 
son and White Star.” 
In the selection of varieties the following factors 
should be taken into account: 
1. Market Requirements. Eastern markets prefer 
head lettuce, although there is an increasing demand for 
the cos type. For many of the western markets the well- 
known loose-leaved or bunching variety, Grand Rapids, 
finds ready sale. 
2. Soil Adaptation. It is much less difficult to grow 
head lettuce in sandy than in heavy soils. Grand Rapids 
may be grown in all types of heavy soils, and cos is said 
to be well adapted to clay loams. 
3. Climatic Conditions. Some varieties succeed bet- 
ter than others at comparatively high temperatures. 
4. The Season. Varieties differ greatly in their power 
to endure heat and cold. 
5. Method of Growing, whether in the open, the hob 
bed, the cold frame or the greenhouse. 
