128 Self- Incompatibility in Hermaphrodite Plants 

 EXPLANATION OF PLATES. 



PLATE III. 

 All reproduced about twice natural size. 



Nos. 1 and 2 are heads, and 3 the rudimentary achenes of a third head all resulting from 

 self-pollination of a completely self-incompatible plant of chicory; Nos. 4 and 5 are 

 heads, and 3 the fully developed achenes of a third head resulting from a compatible 

 cross-pollination of same plant on the same date. 



No. 7. Stages in development of achenes in a single head of a feebly self-compatible 

 plant to self-pellination ; at a, 14 merely rudimentary achenes ; at Z>, 5 achenes of 

 good size but containing no good embryos ; at c, one seed with fully developed 

 embryo. 



No. 8. Series of stages quite as in No. 7. 



No. 9. Achenes from a self-pollinated head of a plant strongly self-compatible. The 



greater number of achenes containing good embryos. No mere rudiments of achenes 



present. 



PLATE IV. 



View of chicory in experimental plot showing races of vigorous vegetative growth in the 

 ^2 generation of self- fertilized descent. At the right, field label No. 26 marks the 

 Series 10-8-140. To left of label 26 are four rows of two series of the family 12-11-. 

 To the extreme left may be seen bags on very tall plants of Series 10-8-37. 



REFERENCES. 

 Banta, a. M. 1916. " Sex intergrades in a species of Crustacea." Proc. Nat. Acad. 



Sci. Vol. II. pp. 578—583. 

 . 1918. "Sex and sex intergrades in Cladocera.^' Proc. Nat. Acad. Sci. 



Vol. IV. pp. 373—379. 

 Belling, John. 1918. " Lethal factors and sterility." Journ. Heredity, Vol. ix. 



pp. 161—165. 

 CoRRENS, C. 1912. " Selbststerilitat und Individualstoffe." Festsch. Med. Nat. 



Oes. z. 84. Versam. Deutsch. Naturf. u. Arzte, SiXho same, 1913. Biol. Centralb. 



Vol. xxxiii. pp. 389—423. 

 Darwin, C. 1865. " On the sexual relations of the three forms of Lythrum, Sali- 



caria." Proc. Linn. Soc. Bot. Vol. viii. pp. 169 — 196. 

 . 1869. " On the character and hybrid-like nature of the ofTspring from 



illegitimate unions of dimorphic and trimorphic plants." Proc. Linn. Soc. Bot. 



Vol. X. pp. 393—437. 

 . 1876. " Cross- and self-fertilization in the vegetable kingdom," Edition by 



John Murray. 



. 1877. " The different forms of flowers." Edition by John Murray. 



Detjen, L. R. 1916. " Self-sterility in dewberries and blackberries." Tech. Bxdl. 



11, N. Carolina Exp. Sta. 

 East, E. M. 1915. " The phenomenon of self-sterility." Am. Nat. Vol. XLiv. 



pp. 77—87. 

 . 1918. " Intercrosses between self-sterile plants." Mem. Brooklyn Bot. 



Garden, Vol. i. pp. 141—153. 

 and Park, J. B. 1917. " Studies on self-sterility. I. The behaviour of self- 

 sterile plants." Genetics, Vol. ii. pp. 505 — 609. 



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