University of California

Pollination and life history studies of lettuce (Lactuca sativa L.)


H. A. Jones

Author Affiliations

H. A. Jones was Associate Professor of Truck Crops and Plant Breeder in the Experiment Station.

Publication Information

Hilgardia 2(13):425-479. DOI:10.3733/hilg.v02n13p425. April 1927.

PDF of full article, Cite this article


Abstract does not appear. First page follows.


The lettuce crop is a very important one in California, and the product is shipped in considerable quantity throughout most of the year. The production of lettuce seed is also an important industry. While the variety New York is the only one produced for shipping fresh, almost all of the important varieties are grown for seed. The growing of lettuce for seed is confined almost entirely to the delta lands of the Sacramento and San Joaquin rivers and to the Santa Clara Valley. Wherever a large number of varieties are grown in close proximity, there arises constantly the question of the danger of cross pollination. Pollination investigations reported herein were initiated because of this question. The morphological studies reported in this paper were commenced to furnish information needed in order to prosecute more successfully other lines of investigation that have been started on lettuce.

Material and Methods

The lettuce seed used for growing the material for the morphological studies herein reported, was planted at the University Farm, Davis, California, in December, 1923. The variety employed was Iceberg. The material for study was killed in formalin-alcohol solution, then dehydrated and embedded in paraffin according to the usual procedure. Most of the sections were stained in Delafield’s haematoxylin, or safranin and gential violet.

Literature Cited

[1] Carano E. Richerche sull’ embriogenesie delle Asteracee. Ann. di. Bot. 1914. 13:251-301.

[2] Chamberlain Chas. J. The embryo-sac of Aster novae-angliae. Bot. Gaz. 1895. 20:205-212. DOI: 10.1086/327187 [CrossRef]

[3] Coulter J. M., Chamberlain C. J. Morphology of angiosperms 1909. DOI: 10.5962/bhl.title.55207 [CrossRef]

[4] Gates R. Ruggles, Rees E. M. A cytological study of pollen development in Lactuca. Ann. Bot. 1921. 35:365-398.

[5] Knuth Paul. Handbuch der Blütenbiologie 1898. pp.1-697. DOI: 10.5962/bhl.title.23080 [CrossRef]

[6] Land W. J. G. Double fertilization in Compositae. Bot. Gaz. 1900. 30:252-260. DOI: 10.1086/328039 [CrossRef]

[7] Martin G. W. Development of the flower and embryo sac in Aster and Solidago. Bot. Gaz. 1892. 17:353-358. 406-411. DOI: 10.1086/326858 [CrossRef]

[8] Merrell W. D. A contribution to the life history of Silphium. Bot. Gaz. 1900. 29:99-133. DOI: 10.1086/327953 [CrossRef]

[9] Mottier David M. On the embryo sac and embryo of Senecio aureus L. Bot. Gaz. 1893. 18:245-253. DOI: 10.1086/326945 [CrossRef]

[10] Nawaschin S. Über die Befruchtungsvorgänge bei einigen Dicotyledonen. Ber. Deutsch. Bot. Gesell. 1900. 18:224-230.

[11] Oliver Geo. W. New methods of plant breeding. U. S. D. A. Bur. Pl. Ind. Bul. 1910. 167:1-39. DOI: 10.1093/jhered/1.1.21 [CrossRef]

[12] Schwere Siegfried. Zur Entwickelungsgeschichte der Frucht von Taraxacum officinale Web. Ein Beitrag zur Embryologie der Compositeen. Flora. 1896. 20:32-66.

[13] Small James. The origin and development of the Compositae. New Phytol. 1918-1919. 17:13-40. 69-94, 114-142, 200-230; 18: 1-35 65-90, 128-176. DOI: 10.1111/j.1469-8137.1918.tb07262.x [CrossRef]

[14] Souèges M. Rene. Embryogenie des Composées. Les premiers stades du développement de l’embryon chez le Senecio vulgaris L. Compt. Rend Acad. Sci. Paris. 1920. 171:254-256.

Jones H. 1927. Pollination and life history studies of lettuce (Lactuca sativa L.). Hilgardia 2(13):425-479. DOI:10.3733/hilg.v02n13p425
Webmaster Email: sjosterman@ucanr.edu