The Morphology of Araucaria brasiliensis. I. The Staminate Cone and Male Gametophyte

Abstract

1. The staminate cones are extraordinarily large and have numerous sporophylls with an indefinite number of pollen sacs pendent from the abaxial side of the swollen apex. 2. An almost incomprehensibly great number of pollen grains is produced. 3. The method of differentiating the sporogenous tissue is variable and indefinite. The size of the sporangium and the number of microspores is subject to wide fluctuations. 4. The structures concerned in dehiscence are very fernlike. 5. The chromosome number in the male gametophyte is 8. 6. Prothallial tissue is formed in a manner almost identical with that in the Podocarpineae, but the number of cells so formed is greater. 7. The pollen is shed with numerous prothallial nuclei, stalk nucleus, tube nucleus, and body cell free in it. 8. The pollen does not fall upon the nucellus but upon the ovuliferous scale at a considerable distance from the position of the ovule. 9. About a year elapses between pollination and fertilization. 10. No ovule has yet been formed on the scale at the time of pollination and the pollen tube does not reach the ovule for 5 or 6 months afterward. 11. The body cell is single, at least usually, and large. 12. Two male cells (sperms perhaps) are formed and are usually unequal. 13. There may be a blepharoplast-like body associated with the division of the body cell. 14. Fertilization occurs about the first of April.