246 THE JOURNAL OF BOTANY 



effective agent in this respect is tlie sharp spur upon the external 

 loculus, as noted ahove. As the insect pushes past, in its exit, 

 the stigma falls back into the recdssed portion of the tube. 



EuELLiA PATULA Jacq. (no. 1382) is remarkable for the 

 fugaciousness of its flowers. The buds of the evening open early 

 upon the morning of the day following. By noon the flowers 

 have fallen. Upon a cloudy day or in deep shade their lives may 

 be prolonged for several hours. The corolla is delicate in texture, 

 veined, and of purplish-blue tint, the colour fading rapidly. There 

 are four didynamous stamens, with simple unbearded anthers, 

 hastate in shape as the two loculi diverge below. A rudimentary 

 fifth stamen is often present. The style is long and slender ; the 

 stigma, at maturity, at a shghtly higher level than the upper pair 

 of anthers. The posterior stigmatic lip is rudimentary ; the 

 anterior is spathulate, arching forwards. Its upper surface is 

 covered with irregular papillae, these in turn being beset with 

 minute secondary papillae ; the whole constituting a highly re- 

 ceptive surface. It is the first thing encountered by a visiting 

 insect, which, upon its retreat, pushes it back against the posterior 

 corolla-wall. The sulcus in the posterior corolla-wall noted in 

 the preceding examples is not pronounced ; it is noticeable, how- 

 ever, in the lower part of the tube showing a slight elbow just 

 above the point at which the infundibuliform dilatation of the 

 corolla commences. Style and stigma do not fall with the corolla 

 and stamens. Auto-pollination is probably of frequent occurrence. 



Note. — In a valuation of the characters of the preceding 

 members of representative Acanthaceous genera, Eiiellia patula 

 would occupy the lowest place. Justicia protracta, if only because 

 of its single pair of stamens, the highest. Yet the stigmata in 

 both species of Thunbergia show extreme differentiation, and the 

 interlocking of stamens, style, and stigma in Thunbergia lancifolia 

 must count in an estimate of values. Valuation of characters in 

 plants seems to be much like valuation in the ordinary offairs of 

 life. Appraisement of a particular character will vary with the 

 valuator. A frequent and widely-spread source of difficulty to 

 one who essays classification is the failure of the different whorls 

 of the flower to keep step developmentally. One whorl, or more, 

 may show a higher degree of specialization than the rest. In a 

 general way help is found by noticing that certain whorls tend to 

 associate in an adaptive advance, as, e. g., in the case of corolla 

 and stamens, whose advance together is so" commonly seen. 

 Ovary and calyx, in the epigynous flower, usually show their 

 partnership clearly enough. In the hypogynous flower close 

 relationship only comes after the fall of corolla and stamens. 

 Thereafter they may develop in company. Style and stigma, 

 ephemeral in their function, may make adaptive partnership with 

 those other passing members of the flower, the stamens. 



Thunbergia lancifolia T. And. (no. 1383). The seeds are 

 plano-convex in shape, and resemble a small keelless boat. A 

 light corky rim bounds the edge, forming a small bulwark. As a 

 consequence, the seeds, if thrown into water, always right them- 



