Block · one region of the page, as the scanner read it. It may hold a whole story, part of one, several, or an advertisement; stitching blocks into articles is the next step. Text is supplied OCR.
Page 12 · column 2 of 4 · from the scan, no model involved
Photos courtesy of Jim Lawrey Ragweed Pollen the ovules develop into seeds. In mature seeds the female gametophyte supplies the embryo with food until it can grow into an independent plant. Longevity of pine cones depends on the sex. Male pine last only a few weeks and fall off after pollination. Female cones can persist for many years even after seeds are produced. ^ The longevity of pollen grains depends on where they fall. Remember, males (pollen r ‘Wk grains) have one mission in life — meeting ■Jjjjg a female. If they don’t fall inside a female cone (and most don’t), they die. The lucky few that get lodged inside a female cone THIS spring must wait there until NEXT spring when female gametophytes are mature and males can finally accomplish their genetic mission. Pollen profusion Given the extremely low odds of a male-female encounter in wind-pollinated plants like pines, they typically compensate by producing HUGE numbers of pollen grains. It’s been estimated that for every female waiting inside an ovule there are over a million male pollen grains. Animal-pollinated plants with attractive and showy flowers generally produce fewer but larger and stickier pollen grains. These sometimes get blamed for causing allergies, but it’s almost never their fault. As an example, fall allergies are most severe when goldenrods are blooming, but it’s the inconspicuous wind-pollinated ragweeds blooming at the same time that are ... probably responsible.
86.2%