INTRODUCTION. XXXI 



mention. It is as well, however, to remark, that the separation of 

 styles is commonly a sign of the apocarpous state of the ovarium, 

 provided the latter is not very apparent otherwise ; and the cohesion 

 of the styles is constantly an evidence of the contrary ; and in this 

 view the Elder and Hydrangea tribes may be justifiably separated 

 from Caprifoliacese. 



The Stigma seldom offers any good characters. In some cases, 

 however, advantage is taken of it, as in Linese, the capitate stigmas 

 of which distinguish them from Caryophylleee, in which they occupy 

 the whole inner face of the styles ; and in Goodenoviee, Scsevolea), 

 and Brunoniacese, there is a peculiar membranous appendage en- 

 veloping the stigma, and called an indusium, which distinguishes 

 those orders from all others. 



The number of the Ovula (that is to say, whether they are 

 definite or indefinite,) is frequently an important difference, as, for 

 example, between Campanulacese and Compositse, Goodenoviae and 

 Sceevolese ; but while I think considerable value usually attaches to 

 this, it must not be forgotten that there are exceptions to it in 

 several instances, especially in Caprifoliacese, if Hydrangea really 

 belongs to that order, and Fumariaceee and Cruciferye. — The posi- 

 tion of the ovula is much more essential than their number, and 

 may be considered as one of the most valuable forms of structure 

 that can be taken into account. It is uniform in Composita;, 

 Valerianese, Umbelliferae, and others, and it constitutes an absolute 

 distinction between Artocarpese and Urticese ; but in Sanguisorbeee, 

 Pedalinese, and Styracese, both erect and suspended ovules co-exist ; 

 this union of the two positions occurs in a most remarkable degree 

 in Penseaceae ; and among Violacese, the genus Conohoria offers, 

 according to M. A. St. Hilaire, {PL Usuelles, No. 10,) an instance 

 of three kinds of direction in as many species; in C. Lobolobo, the 

 ovula are ascending ; in C. Castaneaefolia, they are suspended ; and 

 in C. Rinorea, one is suspended, one ascending, and the inter- 

 mediate peritropal, or at right angles with the placentae. — The 

 situation of the foramen of the ovulum is a circumstance which 

 should always be taken into account, because it indicates with 

 certainty the future position of the radicle, which it is of first-rate 

 importance to ascertain, but which will be more properly spoken of 

 in considering the value of distinctions drawn from that source. 



The ripened ovarium is the Fruit. The differences in its 

 structure are of the same nature as those of the ovarium, and need 

 not be repeated. Its texture and mode of dehiscence are the 

 principal sources of distinctions, but they perhaps deserve as little 

 attention as any of which botanists make use. It is true that the 

 fruit of all Grossulacea? is baccate, of all Labiatai indehiscent, and 



