The Vassar Arboretum is a collection of 230 species of trees gracing the 1,000-acre campus of Vassar College in Poughkeepsie. Ever since the Vassar class of 1868 dedicated a Swamp White Oak as its class tree, the arboretum had expanded, and every April dozens of flowering trees put on a show that can't be topped in any single location in the glorious Hudson Valley.

A map of the arboretum first published in 1975 is unfortunately out of print, and many of the trees are not labeled. On a recent balmy Sunday afternoon, I strolled the campus carrying the old map and a copy of "Dirr's Hardy Trees and Shrubs," hoping to design a simple tour for lovers of spring-flowering trees.

The blooming periods of the Vassar flowering trees vary depending on the species and the weather. Generally speaking, the star magnolias and the cherries bloom first, as early as April 10, so they will no doubt be past their prime by now. The dogwoods, redbuds, shadblows, callery pears and later species of magnolias should be in peak bloom this week, with the crabapples putting on their best display a few days later.

Begin your tour of the Vassar arboretum at the main gate alongside Raymond Avenue. If you walk straight ahead to the Main Building, you can get a campus map (without the trees) or you can download one from www.vassar.edu. Back at the main gate, turn right toward the Chapel, past a lovely Sergeant Cherry that was spectacular at the time of my visit. At the chapel, turn left toward Main and you will pass a dainty pink dogwood on your right. Dogwoods are native to the Northeast. A few years ago, many fell victim to anthracnose disease, but the ones that survived are flourishing. Another dogwood, red flowered, is just southwest of Main Building.

To the left of the front door of Main, on the other side of a blinding circle of tulips (I guess there are no deer in this part of the campus) is a Zumi crabapple. Crabapples are the most stunning of flowering trees, but the native varieties often drop fairly large fruits that make a mess on porches and walkways. The Zumi has tiny bright red fruits that cling to the tree.

Behind Main, in front of the bookstore, you'll see a magnificent cucumber tree magnolia, with gigantic blossoms, but they are often missed because the flower petals are green. Walking toward Swift Hall, you encounter the class of '73 tree, a saucer magnolia, which Michael Dirr calls the "quintessential hybrid magnolia." Since it's native to the South, the blossoms are often killed by a late frost, but not this year.

To the north of Swift is a white flowered redbud (is that an oxymoron?), a native relative of the common pea, which you will believe when the pod-shaped fruits eventually appear. Continuing north, my favorite Vassar tree, a jaw-dropping Bechtel's crabapple stands in front of the old observatory. Further to the north is a petite yellowbird magnolia, with a plaque dedicating it to Estéé Lauder.

Circle around past the all campus Dining Center framed by saucer magnolias, with a precious yellow-blossomed corneliancherry dogwood perched on the corner. Heading south in front of Lathrop and Strong houses, the Kwanzan cherries are out of bloom by now, but eventually you'll be assaulted by a towering dawn redwood, admittedly not a flowering tree, but nonetheless one of the most magnificent specimens on campus, planted by the class of 1957.

Turning right at another crabapple, you'll see a shadblow, another Hudson Valley native so named because it blooms when the shad run up the river in front of Rockefeller Hall. A grove of corneliancherry dogwoods stands on the corner.

Conclude your tour with a stop at the world-famous (named one of New York's 10 most historical trees) London Plane Tree in front to the Library, a giant relative of the Sycamore placed by the class of 1906.

Nowadays the arboretum is under the supervision of longtime Vassar horticulturist Jeffrey Horst. He loves to show groups around the arboretum, but the tours are not regularly scheduled. You can contact him at (845) 437-7000. Jeff suggests that you check out the Apple Orchard, and the callery (Bradford) pear trees around sunset lake in the southeast quadrant of the campus for a stunning show of spring color.

The Vassar College campus is open to the public every day, from dawn to dusk.

Mark Adams is president of Dutchess County Farm Bureau and New York State Representative for the nursery/greenhouse industry to the American Farm Bureau Federation.