Parliament's fall session got underway Monday with tributes to Jack Layton in the House of Commons by party leaders and the late NDP leader's wife, Olivia Chow.

Speaker Andrew Scheer opened the session by officially announcing a vacancy in the riding of Toronto-Danforth, due to Layton's death from cancer last month, and then he called on Layton's temporary replacement as Official Opposition leader, Nycole Turmel, to rise and deliver remarks about her colleague.

She stood next to Layton's seat, which was symbolically left empty.

Turmel spoke about Layton's legacy, his passion for social justice and youth, and she called on MPs on all sides of the Commons to carry on his work.

"Jack Layton believed so much in the power of democracy and of this Parliament. I invite all honourable members in this House to join me in picking up this torch and making this an institution in which Canadians can be proud," Turmel said.

"Jack Layton improved the tone of the debate in Parliament. He firmly believed we could have passionate disagreements without being disrespectful or disgraceful to each other. Let us all honour his memory by conducting the next session of Parliament in this spirit," she said.

Turmel and many other MPs were wearing orange ribbons to honour Layton.

Harper pays tribute

Prime Minister Stephen Harper spoke next on behalf of the Conservatives. He said one of the pleasures of working on Parliament Hill is the surprising friendships and affections that develop among political opponents.

"In the case of Jack Layton, I believe that all of us developed this affection, inexorably. His passion, his perseverance, his ability to be at once tough and cheerful, would eventually win over even those who most strongly disagreed with him," Harper said.

Harper recalled Layton's devotion to Canada, and said he was always full of optimism and goodwill despite the political battles he was embroiled in with his opponents.

"When we look now across the floor it is hard to believe he isn't still there," Harper said. The prime minister also acknowledged Chow, saying that like her husband, she has won the respect and admiration of everyone in the House of Commons.

"In recent weeks she too has displayed the courage and dignity which we can only hope would emerge in us were we to suffer such a loss," he said.

Interim Liberal Leader Bob Rae was emotional while delivering his tribute to Layton. He talked about Layton being gone, but said his warmth, his values and his strength "will never die."

"We have lost a colleague and a friend, the country has lost an important political leader, an important political presence and my colleague from Trinity-Spadina has lost a husband and a partner," he said, referring to Chow. "To her, we offer our warmest condolences."

Louis Plamondon spoke on behalf of the Bloc Québécois and Green Party Leader Elizabeth May also delivered a tribute, and thanked Harper for providing a state funeral for Layton.

Chow thanked Harper for the honour when she spoke, and for his personal support in his remarks. She said all of her colleagues have been supportive and she thanked them for passing on condolences from their constituents.

"The generosity of Canadians has been a source of great strength for me and for our family in these past weeks," said Chow.

She said it's more difficult now to be hopeful and optimistic without Layton at her side, but that she's determined to carry on with their goal of making Canada a better place.

"I am resolved to move forward to help make the dreams that Jack and I shared for 30 years a reality for future generations," she said.

A moment of silence was observed following the tributes.