Wedgwood seems to have been looking directly at silver designs when they developed this shape.  Deep fluting around the lower portion echoes the gentle curves of the body, an effect one can imagine in silver prototypes.  In contrast, the floral decoration seems to emulate silver repousse work. Wedgwood underscores the fluting and floral motifs by executing the fluted body in their soft taupe color drab stoneware and the floral detail in contrasting white, all lightly glazed.  

The one detail we suspect the potter added was the (somewhat impractical) sheaf of wheat finial which Wedgwood used on other stoneware tea shapes.

Whatever the sources, the combination of silver shapes, Wedgwood's tasteful taupe brown body, white floral detail and rustic sheaf-of-wheat finial all combine for what must have been a very satisfying tea table experience.  

A reprint of a 1914 catalog page featuring basalt teawares identifies this shape as "Etruria"  (Robin Reilly, Wedgwood, Volume II; p. 450). While the catalog dates from 1914, Reilly is quick to add that the shapes date as far back as the early nineteenth century. We do not know when the "Etruria" monicker was applied to this shape. 

Phillip Miller and Michael Berthoud, An Anthology of British Teapots ( p.230, plate 1376, 1378) include this shape among "Oval Moulded Earthenware" teapot shapes.  According to their notes, Wedgwood introduced the shape c.1815 and continued production through the 1840's.