BRACTS AND FLORAL LEAVES. 89 
be out of place in an elementary book like this. Two further 
points may be noted about the purple orchis. The labellum pos- 
sesses a large spur, and the flower is so twisted round that upper 
parts are really lower, and vice versd (fig. 52). 
The gamopetalous corolla usually presents certain well-marked 
regions. The united part is termed the tube, while the more 
or less distinct teeth or lobes which represent the free ends of 
the petals form the imb. The commencement of the tube is 
the throat. Sometimes the limb is absent, and the number 
of petals is then found by counting the most prominent veins 
(z.e., midribs of the petals), or is inferred by comparison with the 
calyx and also with the corollas of closely related plants. The 
principal shapes found among regular forms are the following, 
in which the tube becomes of greater relative importance as we 
proceed in the series. In potato and forget-me-not the tube is 
extremely short, and the limb flat and spreading, giving a certain 
resemblance to a wheel, whence the term rotate or wheel-shaped. 
A corolla of this kind may be slightly irregular, as in speedwell. 
The word stellate is applied to cases where the tube is very short 
and the spreading lobes very pointed, as in cleaver, while a saucer- 
shaped corolla differs from a rotate one in being concave instead 
of flat. If in a wheel-shaped or saucer-shaped corolla the tube 
were considerably elongated, we should get a salver-shaped (hypo- 
crateriform) example, as in primrose and plumbago. A bell- 
shaped or campanulate corolla, like that of harebell, Canterbury 
bell, &e., gradually enlarges almost from its beginning, the limb 
being small. An irregular example of the same is foxglove. A 
bell-shaped corolla by contracting at its mouth would become 
inflated or urn-shaped (urceolate). The different kinds of heath 
(but not heather) are good instances. Tubular and funnel-shaped 
corollas are respectively cylindrical and conical, the limb being very 
small or absent. Thistle-florets and convolvulus are examples. 
The irregular gamopetalous corolla may be on ad or markedly 
so. The speedwell, mentioned above, is an = 
example of the former condition, while in 
the latter case a labiate or lipped form is 
the commonest. The white (or red) dead 
nettle is a typical illustration (cf. fig. 43). : \ 
Since in this plant (and allied forms) there yyg. 45. -rabiate Corolla 
are five sepals, the odd one posterior, it is of Sage. 
evident that of the five alternating petals the odd one must 
be anterior, so that the lower lip consists of three petals, and 
the upper lip of two. In this particular example the two 
petals forming the upper lip are so closely united that its 
double nature cannot easily be recognized, but the union is not 
