The birthday of Queen Mother Elizabeth of Britain has just been celebrated by an omnibus issue that brought out many more stamps than a similar one five years ago, but then five years ago she was only 80.

For her 85th birthday, 40 countries, some but not all of them members of the Commonwealth, have put out sets of stamps for Britain's popular "queen mum."

She has appeared on two even larger omnibus issues. The first was the coronation omnibus of 1937, when her husband, King George VI, ascended the throne. Fifty-five nations took part.

More than 70 countries participated in the omnibus issue of 1948 marking the 25th wedding anniversary of the royal couple.

In each participating country, the omnibus issue consists of a set of four stamps and a souvenir sheet, all sets adhering to the same format. Under the format, the opening low value of the set depicts the queen mother with a member of the royal family, followed by a stamp showing her at a public occasion. The concluding high value, the same in all sets, pictures her with her great-grandson Prince Henry, after the christening of the infant. The picture was taken by Lord Snowdon, a distinguished photographer and the former husband of Princess Margaret.

The souvenir sheets all depict her using forms of transportation: the royal yacht, the liner Queen Elizabeth, a barge, a gondola, carriages and cars, pony carts and planes.

The initial stamps of the sets, predominantly based on old private photographs, have the center vignette in monochrome. The other three in each set are multicolored. Above the circular vignettes are tiny bows and heraldic lions in what amounts to a graphic pun on the queen mother's family name of Bowes-Lyon. Below the vignettes are decorations from the coats of arms of each issuing entity.

The earliest of the opening stamps show her as a 2-year-old in 1902 and at Glamis Castle in 1909, dressed for a dancing lesson. The castle in Scotland where, according to Shakespeare, Macbeth murdered King Duncan was her home from the age of 4 until her marriage to the then Duke of York in 1923.

Scenes on the second stamps of the sets show her with her two daughters, and with her grandchildren individually and collectively, on formal and family occasions.

The third stamp in each set epitomizes the energy and warmth that have made her so popular. She is depicted at various functions, such as visits to schools and hospitals, gardens and universities, ballet and opera.

The sets and the accompanying souvenir sheets fall into two categories: stamps showing the queen mother and varous members of the royal family, and stamps highlighting her various activities. She is shown visiting a children's ward of a hospital, chatting with children at a sand pit in a tour of London Gardens, visiting the disabled, attending the ballet, attending church services, at the races and indulging in one of her favorite recreational activities -- fishing.