The show includes several miniature masks that are not worn, but carried as power symbols. (Private collection, New York)

Dreams are the inspiration for much of the art in the National Museum of African Art’s latest exhibition. It certainly looks like a shadow realm. Illuminated by a twilit scheme meant to evoke late-afternoon sunshine filtered through a dense canopy of leaves, “Visions From the Forests” features mask after mask, many of which seem to have sprung from a restless mind. The whole show has the feel of a power nap: more stimulating than sleepy.

The hallucinatory implication of the title is not just a metaphor. In the tradition of the Dan people of West Africa’s upper Guinean rain forest, where this art comes from, the sandman is quite literally the maskmaker’s muse. For the Dan artist, as the wall text explains, a mask “is typically created after a dream in which someone encounters a forest or household spirit.” The mask, then, is imagination made flesh.

Of the 75 objects on display — which include silver jewelry, stone carvings, colorful fabrics and horns made of ivory — 33 are wooden masks carved by the Dan, the Vai, the Mende and other peoples of Sierra Leone, Liberia, Ivory Coast and Guinea. The most striking of these are several ­helmet-style masks that cover the entire head.

Ten of them were created for use in female initiation rituals. Sometimes topped with animals or other ornamentation, they’re characterized by elaborately stylized coiffures, along with prominent foreheads, teeny faces and thick, exaggerated neck folds that represent the creases (i.e., the wisdom) that come with maturity.

On several object labels, you’ll notice that the name of the artist is given. This may seem a small thing, but it’s a bit of a departure. In the typical African art show, most objects are identified only by the culture, simply because the lack of documentation makes it hard to track down attribution. This show is different.

One mask, shown with the full-body costume of cloth and raffia that accompanied it, was created by Ansumana Sona. Another is by Amara, known as Pa Jobo. Jobo also contributes a standing female figure.

That level of detail, of course, is evidence of another kind of vision. While honoring the aesthetic variety and virtuosity of the objects on view, the show also celebrates the connoisseurship of the man who collected them. Everything on display is from the personal collection of William Siegmann (1943-2011), a former curator of African art at the Brooklyn Museum who began purchasing African art — mainly from Liberia and Sierra Leone — while working in Liberia between 1965 and 1987.

Although a number of works in the show belong to his estate, many have been dispersed to various institutions. Several are on loan from the Minneapolis Institute of Arts, which organized the show and to which it will travel next. (Siegmann originally hailed from Minneapolis.) Some are on loan from the Brooklyn Museum. Three are in the collection of the National Museum of African Art, including two masks and an ornamental snuff container fashioned from a ram’s horn. One of those masks, by the Sherbro artist Kaiwa, is among the show’s most arresting helmet masks. It’s crowned by a carved bird and two snakes, symbolizing the tension between man’s divine and animal natures.

“Visions From the Forests” is somewhat different from most single-collector shows in that it does not reveal terribly much about the idiosyncrasies of the collector’s taste. The works on view include both serious and comic masks; two-foot-tall masks used for entertainment; and personal, pocket-size masks designed to be carried in a pouch as tokens of power.

That breadth and depth tells us something about Siegmann — that he wasn’t just collecting what he liked, but what mattered.

The Story Behind the Work

One of the most unassuming objects in “Visions From the Forests” happens to be among the first pieces collected by Siegmann. It’s a simple piece of striped indigo fabric that he bought on his third day in Liberia, where he had begun teaching under the auspices of the Peace Corps in 1965.

As Siegmann reminisced in 2011, “It was a textile from the father of one of my students, who had a beautiful blanket that he was selling in order to help pay tuition.”

Christine Mullen Kreamer, the National Museum of African Art’s deputy director and chief curator — and an old friend of Siegmann’s — says that in this case the collector may have been motivated, at least in part, by sentiment. According to Kreamer, the man she calls “Bill” was known for bringing to bear all three aspects of the collector’s art: a discerning eye, a keen mind and an open heart.

— Michael O’Sullivan