1886-87.] Affinities of Scrophidariaceoi. 103 



nearly impossible to distinguish at what point they enter the 

 axis. In extreme cases the united bundles form a complete 

 fibrous ring at the base of the corolla. I believe that usually, 

 if not always, the bundles passing into the corolla are the 

 same as the commissural bundles observable in the calyx. 

 Hence, if the calyx is normally 4-lobed, the bundles supplying 

 the corolla will be four, alternating with the median bundles 

 in the sepals. 



Yet in certain abnormal cases five sepals occur in the calyx — 

 quite as often there are indications of six — inasmuch as when 

 one sepal tends to become bifid, the one opposite to it shows 

 also a bifid character, suggesting unmistakably the modifi- 

 cation of an extra pair of the decussate leaves of the stem. I 

 have also found a calyx with seven lobes. 



Two explanations as to the usual orthogonal arrangement 

 may be brought forward. One is, that instead of the suppres- 

 sion of a posterior sepal, union of two anterior ones has 

 occurred. There is no confirmation of this offered by the 

 nervation in the lower sepals — insertion of another bundle or 

 bifurcation occurring quite as often in a lateral sepal as in the 

 anterior one. 



]\Ioreover, suppression of a sepal is the usual form in which 

 reduction takes place in the calyx, and this suggests another 

 explanation, which is borne out by the apparent tetramery in 

 Pcntstemon digitalis, instanced by Brauu in the paper already 

 referred to. 



In this case the orthogonal condition may result from the 

 suppression of one of the anterior sepals — not the posterior 

 one. This appears likely when it is observed that the 

 staminode, opposite the posterior sepal, remains in the ortho- 

 gonal condition just as in the pentamerous form ; whilst one 

 of the fertile anterior stamens, and by inference the superposed 

 sepal, has disappeared. 



Perhaps the fact that at times a posterior stamen is present 

 in certain species of Calceolaria * may be considered as 

 strengthening this latter suggestion. 



In any case it is difficult to account for the decision of 

 Braun in reference to the genus, " that Calceolaria must be 

 looked upon as a normally tetramerous flower of the order 

 Scrophulariacese." How can a plant be normally tetramerous, 



* Vide Bentham aud Hooker's Genera Flantarum. 



