PLANTS JAVANICLE RARIORES. 591
wanting. This modification is necessarily accompanied by a different aestivation, which in all the other genera is quincuncial, the lateral lobes of the lower lip overlapping the upper, which covers the middle lobe of the lower. The spur of the tube is found only in one of the two species of Staur anther a.
The number of antheriferous Stamina, or the difference between the diandrous and didynamons plants of the tribe, is not always of much value ; for in Bidymocarpus there are several didynamous species which certainly do not form a natural section. Stamina inclma and exserta generally mark distinct genera, but yet not in all cases. The differ- ence between parallelism and divarication of the lobes of antherae is always, I believe, of generic importance. The various degrees of confluence of the divaricate lobes, and the apparently peculiar dehiscence in some of its modifica- tions, seem not to be of equal value.
The Stigma exhibits various remarkable differences, some of which are considerable, though not always of equal, value in the definition of genera. The most im- portant of these, and which hitherto has been overlooked, is the abortion, or great reduction in size, of the upper lip, while the lower is proportionally dilated, and, in some cases, deeply divided. Thus in Chirita, in which the stigma is described as bilamellar, both lamellae belong to the lower lip, And in many species of Didymocarpus the apparent obliquity of stigma arises from the abortion of the upper lip, and the lamellar expansion of the lower, which, however, is never divided as in Chirita. In several genera the lips are equal, and either lamellar or so short as to be hardly distinguishable ; in other cases there is no trace of division. These different modifications, in most cases, mark the limits of genera.
As some of the most important characters of the tribe reside in the structure of Ovarium and Pericarfium, so the principal natural divisions are founded on modifications of the same organ. The ovarium may be in all cases de- scribed as properly unilocular : though, from the approxi- mation and slight cohesion of the parallel portions of the
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