Productiveness and Degeneracy or* the Irish Potato 
15 
tuber parts named. 
This plate is prepared to make clear the definitions herein given 
of tuber parts and defects. The plate is numbered from 1 to 16, as 
below explained. 
3 2 1 
TUBER NOMENCLATURE; PLATE VIII. 
# . 
1. Longitudinal section of a tuber with defects. 
2. A portion of the main stem of a potato plant. 
3. A Pearl tuber with recessed stem end. 
4. Leaf Yoke or line of separation of the leaf from the stem and 
corresponding to the eye yoke at No. 5. 
5. The Bye Yoke on a good tuber has only the central portion 
On degenerate tubers, it is stronger, and on aerial tubers runs 
down at the ends as indicated by the dotted line at 5. 
6. The Yoke Point is absent on the best tubers but is strong on the 
sexual tuber shown on Plate VI, page 2. No. 6 corresponds 
to No. 12, the stub of the leaf stalk. 
7. A Knot or protruding tubered branch, accompanied by a deep 
eye pit. 
8. The eye pit is here deep. 
9. A deep eye pit without a knot. 
10. A heavy eye brow and a deep eye pit. 
11. A compound eye and a deep eye pit. 
12. The stub of a leaf stalk, corresponds to No. 6, the yoke point. 
13. Bye blinds are little bracts just outside the sprout tips. 
14. A side sprout tip. 
15. A main sprout tip. 
16. The group of eyes here suggests the growers’ name, seed end. 
