The renowned primatologist Jane Goodall has admitted to using passages without citation from websites including Wikipedia in her new book about humankind's relationship with nature.

A Washington Post reviewer spotted the phrases in her book Seeds of Hope, which was co-written with Gail Hudson. Goodall told the paper: "This was a long and well-researched book and I am distressed to discover that some of the excellent and valuable sources were not properly cited, and I want to express my sincere apologies."

The conservationist, best known for her work with chimpanzees in Africa, said she would discuss the concerns on her blog, though nothing has yet been published on the site.

The paper highlighted one passage on boxes of seeds, which read in the book: "Bartram's Boxes, as they came to be known, were regularly sent to Peter Collinson for distribution to a wide list of European clients." The Wikipedia entry reads: "Bartram's Boxes as they then became known, were regularly sent to Peter Collinson every fall for distribution in England to a wide list of clients."

A section in the book on trees reads: "In ancient Egypt, the sycamore was especially revered — twin sycamores were believed to stand at the eastern gate of heaven through which Ra, the sun god came each day." A site called Find Your Fate says: "Twin Sycamores of turquoise were believed to stand at the eastern gates of heaven, from which the sun god re emerged every day called The Big Tree on The Eastern Horizon."

Mary Lewis, Goodall's personal assistant and vice-president of outreach of the Jane Goodall Institute, told the Guardian that Goodall – who talks at public events around the world – had been "heavily involved" in the writing of the book: "Jane does a vast amount of her own writing. It was a complicated and thoroughly researched book. Gail [Hudson, the co-author] worked closely with her. This has been blown out of all proportion."

Grand Central, the book's publisher, told the Washington Post: "We have not formulated a detailed plan beyond crediting the sources in subsequent releases."

Hudson said she had no comment.

The book has received mixed reviews, with the Boston Globe's reviewer writing: "In general, Goodall is more of an inspiring human being than an inspired writer; at times one can have the impression that one is reading the author's lecture notes."