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 labellnm pos- 

 sesses a large spur, and the flower is so twisted round that upper 

 parts are really lower, and vice versa (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 limb. 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 

 {i.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, &c, 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 funnd-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 slightly 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 

 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 



