Mark Rothko, Untitled (Yellow, Orange, Yellow, Light Orange), 1955, oil on canvas, 81½ by 60 inches. Estimated at 20-30 million dollars.

Highlights from the art trove of a famous and storied collector come to auction tonight at Sotheby's New York in a sale estimated to bring as much as $100 million, led by a Rothko canvas tagged at up to $30 million.

The late Rachel Lambert "Bunny" Mellon, a reclusive and wealthy art collector and amateur horticulturist, left behind a vast estate of fine art, jewels and decorative arts when she died in March. Tonight's is the first of eight sales this month. Mellon's grandfather, a pharmaceutical mogul, invented Listerine. Her second husband was Paul Mellon, son of financier and treasury secretary Andrew Mellon. Paul Mellon was on Fortune magazine's first list, in 1957, of the wealthiest Americans, with an estate valued at up to $6 billion in modern dollars.

Last week, Christie's and Sotheby's Impressionist and modern art evening sales brought in, respectively, $165 and $422 million. The Sotheby's sale was led by a $100-million Giacometti sculpture, the Christie's sale by a Manet canvas that brought $65 million from the Getty Museum, nearly doubling the artist's previous auction record.

Sotheby's Bunny Mellon offerings include 43 examples by artists from Picasso and Seurat to Hopper and Diebenkorn (the latter is the most-represented artist in the sale, with eight works). All are paintings except for two sculptures by Diego Giacometti, younger brother to Alberto. The Rothko work for sale is Untitled (Yellow, Orange, Yellow, Light Orange), a sunrise-hued canvas from 1955.

The earliest piece is a 17th-century oil-on-copper still life by the Dutch painter Ambrosius Bosschaert the Elder, estimated to fetch up to $4 million. Most of the many hundreds of other paintings and thousands of objects-from silverware to baskets to gardening hats-were stored in some 20 buildings at Oak Spring Farms in Virginia, the working dairy farm that was Mellon's primary residence. (She also had homes in New York, Washington, Paris, Cape Cod, Antigua and Nantucket.)

Sales of Mellon's collection continue throughout November: jewels, antique objects and accessories on Nov. 20-21, and furniture, porcelain and decorative art on Nov. 21-23.