ARTHUR C. GIBSON, MEMBG Director
The next time that you visit The Nest, along the north fence observe Cornutia grandifolia (Schlechtendal & Chamisso) Schauer (Family Verbenaceae), a small evergreen tree (6 meters) and relative of Vitex lucens (featured in the summer MEMBG newsletter). We are rather proud of our Cornutia, which possesses delightful blue flowers from late spring through early fall. The genus was named by Linnaeus for Jacques-Philippe Cornut, a 17th century physician of the medical faculty in Paris, who also published early accounts of plants from eastern North America (1635). Cornutia grandifolia is native to Central America.
Like most verbenads, Cornutia has opposite decussate leaf arrangement along its quadrangular stems. Leaf blades on our specimen are ovate to broadly ovate or elliptic and range on typical shoots from 16 to 28 centimeters long and 8 to 13 centimeters wide, with petioles of 3 to 6 centimeters. However, on vigor suckers, which can have extremely long internodes, some blades become 48 by 35 centimeters-a surprisingly large simple leaf and worthy of the specific epithet grandifolia. Robust internodes may form translucent wings along the four edges, and although not a stipule, at each stem node arises a pair of flaplike projections. The blade has an entire margin (or essentially so), acute apex, and attenuate base, being semigloss above and dull and lighter green beneath with a soft roughness due to the presence of short hairs covering all surfaces. These leaves, when crushed, have a slightly medicinal fragrance but are not strongly aromatic like their cousins the mints (Family Lamiaceae).
Inflorescences on C. grandifolia commonly reach half a meter in length and consist of 12 to 20 pairs of cymes, each with dozens of developing flower buds. In the cyme, a terminal flower bud forms, and from its base arises a pair of branches, each terminating in a flower bud, and so forth. Of the hundreds of developing buds per inflorescence, less than a couple dozen are rarely open on a given day, but the inflorescence produces flowers for many weeks, even having open flowers when others are forming fruits.
The flower is about 2 centimeters long and has a strongly curved floral tube. The blue petals are fused into a corolla face with three upper lobes and one broader lobe below. Four stamens are exserted from the corolla to come into contact with pollinators. The ovary is superior. Many animals visit these flowers, and in early fall each inflorescence often has a dozen or so purple-skinned drupes up to 1.1 centimeters across, essentially globose but slightly dimpled. Pulp is juicy and cloudy tan, surrounding a hard, dark brown stone (endocarp) that resembles a short clove.