Autumn bonnet fashions from September 1855.

The Monitor, 1855.  Image from The Costumer's Manifesto.

The following is from Godey's Lady's Book, of course!

“PEOPLE,” in the Grundy sense, are beginning to arrive from watering-places and the country, with the first demand of absentees, fall bonnets.  Belgian straws, satin straws of mixed colors, as brown and white, black and white, or Leghorns, are the decided favorites.  The first is trimmed with a mixture of ribbon and black blonde as simply as may be, with perhaps a few field-flowers inside the cap, or a bouquet on one side, mixed with lace.  One of the most elegant we have seen had a large crimson poppy, with a black heart; buds and leaves arranged around it, as above; the strings were, of course, a rich crimson and black ribbon.  This bonnet was appropriately worn with a black silk dress and mantle.  Leghorns are much trimmed with straw in bands, bouquets, rosettes, etc.  Black and white satin straws are the favorite bonnets in half mourning; they have black taffeta ribbon and straw gimps, mingled in loops, bands, and bows.  Those who have had transparent straws through the summer sometimes prefer to have them made up over dark shades of blue or green to purchasing entirely new bonnets.  Most of the fancy braids will do up to look almost as well as new for a second season, particularly French lace straws, and even Neapolitans.  The autumn ribbons are, as usual, very rich in color and variety of shading.  Plaids and strips or moire and velvet, with taffeta, either in the same or contrasting colors, are the favorites.  Never was there a season when ribbons were more in use for dresses, mantles, even chemisettes and  undersleeves.  In all our large cities, “ribbon stores have become a feature.”  They sometimes have embroideries also; but other establishments deal in nothing else.  Every hue of the rainbow—every shade of heaviness or delicacy in material is represented.  Velvet, moire, taffeta, gauze, and mixtures of all these, in widths from half an inch to six inches, are to be found."