Pollen cell. In flowering plants the vegetative tube cell produces the pollen tube, and the generative cell divides to form the two sperm cells. Pollen is produced in the microsporangia in the male cone of a conifer or other gymnosperm or in the anthers of an angiosperm flower. Pollen grains come in a wide variety of shapes, sizes, and surface markings characteristic of the species (see electron micrograph, right). Pollen grains of pines, firs, and spruces are winged. The smallest pollen grain, that of the forget-me-not ("Myosotis" spp.), is around 6 µm (0.006 mm) in diameter. Wind-borne pollen grains can be
Shroud of Turin in Edessa, Turkey. Mark Antonacci argues that the pollen evidence and flower images are inherently interwoven and strengthen each other. However it was subsequently determined that Baruch's work was "scientifically unsafe", and Danin thereafter disowned the publication of this work. Danin stated in 2011, that: "In 2001 we brought most of the slides to Prof. Dr. Thomas Litt who is an expert palynologist and has very sophisticated microscopic equipment. Prof. Litt concluded that none of the pollen grains he saw could be named at a species level. Hence, all the conclusions drawn from previous palynological investigations of Dr. Frei's material