His crisp, black beard is neatly trimmed; his dark eyes crinkle frequently into a smile, and his accent is far more Pennsylvania than Russian.

He is not the man you would most likely pick out of an airport crowd as His Beatitude, the Most Rev. Theodosius, metropolitan of All-America and primate of the Orthodox Church in America, spiritual heir of generations of Russian Orthodox patriarchs.

The choice last October of the 45-year-old churchman, the first American-born prelate to head the Orthodox Church in America, is symbolic of the changes taking place in the church that for nearly two centuries was an "ethnic" church in this country.

Metropolitan Theodosius' visit here last weekend was a holiday highlight for two OCA congregations, St. Nicholas at 3500 Massachusetts Ave. NW, and St. Marks, at 7124 River Rd., Bethesda.

In between the celebrations of the ancient liturgy and greeting the faithful, he traced for a visitor the unique role of his church in American life.

"It began nearly 200 years ago as a mission (of the Russian Orthodox Church) in Alaska," he explained.

Despite that beginning as a Russian church mission, the influx of Russian immigrants during the late 19th century and the successive waves of Russian refugees following both World Wars, the church today has become thoroughly integrated into American religious life, he pointed out.

It is so integrated, in fact, that "at least half the men entering the seminary" to study for the priesthood today come from other than Russian or Slavic backgrounds. "Either they are converts (to Orthodoxy) or their families were converts," he said.

Typical is the bishop who was runner-up in the election for metropolitan at the church's All-American Council held in Montreal last October. He was Bishop Dmitri - Orthodox bishops use only a Christian name - of Hartford, Conn., a former Southern Baptist who converted to Orthodoxy as a teen-ager.

Metropolitan Theodosius' parents emigrated from Galicia, now a part of the Soviet Union, to Canonsburg, Pa., where his father worked in a steel mill.

The church, which a generation ago constituted a haven for refugees or immigrants longing to maintain contact with the familiar language and culture of the old country, has had to swiltch to English in order to retain the young people and to move into the mainstream of American life. Both congregations here conduct English-language services.

"But we still sing in Slavonic and Greek and Russian," the metropolitan noted. "It links us to our past."

For well over a century the church, which was founded by Russian missionaries to Alaska in 1794, was a diocese of the Russian Orthodox Church. But the chaos created by the Russian Revolution 60 years ago plunged the churches here into a kind of limbo.

A 1924 council held in Detroit declared the American churches "temporarily self-governing." It was not until 1970 that the Russian Orthodox Church in the Soviet Union formally acknowledged this status. The present metropolitan - he was then ruling bishop of Alaska - was chosen to go to Moscow at that time to accept the document recognizing the autocephaly - or full independence - of the Orthodox Church in America.

He acknowledged that there has been "some conflict" with another, smaller group of Orthodox Russians in this country who have termed themselves the Russian Church in Exile.

"They take the attitude that they are here temporarily, that they will go back to Russia when it is free," he explained. "For the Orthodox Church in America," he continued, "we feel that this is where we are sent by God and this is why we are here. We have no other place to go; this is where we are staying."

The OCA's adamant stand on restricting the priesthood to males has attracted some disgruntled Episcopalians who are unhappy with their church's decision last year to admit women to the priesthood, Metropolitan Theodosious said.

"They come in mostly as individuals," he said, although he noted that in Kansas City, an entire parish withdrew from the Episcopal Church and moved into the OCA as the Church of St. Theo of Tarsus.

Episcopal prests may become priests of the Orthodox Church, but they must contrast, priestly orders of Roman contrast, prestly order of Roman Catholics are accepted in the Orthodox Church without reordination.

"It's a question of the apostolic sucession," as well as of agreements a ecumenical understanding at the highest levels of the two branches of Christendom, he explained.

While the Orthodox Church will ordain married men as priests, an unmarried priest, once ordained, is not permitted to marry.

The Orthodox Church in America has unabashedly resumed a missionary posture now that it has cut its ties with the mother church.

Its missionary field is right here.

"There are 30 million people who are unchurched (without church membership) in this country," Metropolitan Theodosius pointed out. He believes his church had something to offer them.

"We have a church that is Bible-centered, that is centered around the Gospel placed on the altar, that is a traditional Christian church," he said. "And while the (church) government is hierarchical, the participation of the laity is encouraged."

The All-American Council of the church in Montreal last October, the fifth since the Orthodox Church in America become independent, permitted women to participate for the first time as observers.

Metropolitan Theodosius said his church has missionaries at work throughout the United States, some parts of Canada and in Mexico.

As for the new congregations that the church is forming, he said, "The nucleus may be Orthodox (members) who have resettled in another part of the country, but our missionary effort is to the unchurched."