376 



POLYGALACE.E. 



[Hypogynous Exogens. 



Milkworts are remarkable, among other things, for the u'regularity of their flowers, 

 which is such as to obscure, in a great measure, the relative position of the sepals and 

 petals. The calyx apparently consists of but three pieces, which are usually green, and 

 like sepals in theu' common state ; but their real number is 5, the two colom'ed lateral 

 petal-hke bodies sometimes lymg \\'ithin the apparent sepals, being in reality part of the 

 series of the calyx. The corolla is mostly monopetalous, and, if carefully examined, formed 

 of 3 pieces ; namely, the keel and two petals, all blended together. We have, therefore, 

 an abortion of two petals, according to the laws of altei'uation. But this is not all ; 

 there is not only an abortion of two petals, but of those two which would, if present, be 

 fomid right and left of the keel. The monopetalous corolla is, therefore, formed by the 

 cohesion of the two posterior and the anterior petal of a pentapetalous corolla, of which 

 the two lateral petals are suppressed. The keel has an appendage of an anomalous 

 character, called technically a crest, and often consisting of one or even two rows of 

 fringes or divisions, originating not from the margin, but from within it, and sometimes 

 cohering in a common membrane at theu" base. Aug. de St. Hilaire has sho\Mi that 

 this crest is nothmg more than the deeply-lobed middle segment of a keel, with these 

 lobes m such a state of cohesion that the central lobe is pushed outwards, while the 

 lateral ones cohere by their own margins and with its back. The stamens are only 8 : 

 two therefore are suppressed. This relative position of the fifth sepal and petal res- 

 pectively, was first mdicated by Brown. 



Milkworts are stationed by De Candolle between Sundews and Poreworts (Treman- 

 draceae), and in the immediate vacinity of Violetworts. With the latter they were 

 thought to be related on accomit of then* hypog)^lous stamens, h-regular flowers, and 

 cucullate stigma ; and with Poreworts on accovmt of the carmicula of their seed. To 

 Fumeworts they approach in the general aspect of their flowers, and in httle more. 

 Leguminous plants are, notv\ithstanding theu' perigynous stamens, an Order with which 

 ]Milkworts seem at first sight to have some aftinity ; the irregularity of corolla is of a 

 similar nature in both ; there is m Leguminous plants a tendency to suppress the upper 

 lateral petals in Erythrina, as in Polygala, and the ascending du'ection of the style with 

 a cohesion of stamens are characters common to both Orders. ]Many additional obser- 

 vations are made to the same eff'ect by St. Hilau'e and Moquin-Tandon, who, moreover, 

 compare the Order vWth Rueworts ; but those authors appear to have finally decided 

 upon the true position of Milkworts being in the vicinity of Soapworts ; remarking that 

 " the calyx of the latter is unequal, the corolla very u*regular, and the ovary of Schmidelia 

 usually 2-celled and 2-seeded, hke that of Polygala. Moreover, a great part of the 

 genera of that Order have, with a calyx of five div-isions, a corolla with four petals, and 

 the place of the fifth is manifestly vacant. This suppression is not exactly the same as 

 what is observed in the coroUa of Polygala, where there are only 3 petals v\ith 5 sepals ; 

 but the suppression has more analogy -with what concerns the stamens, since with a 

 quinary number in the calyx each Order has eight antheriferous filaments." In this 



view I fully agi-ee. The imsjTn- 

 metrical flowers, moi'e especially 

 manifested in the reduction of the 

 number of carpels to 2 or 3 in a 

 structure other\\-ise quinary, the 

 definite o\ades,the twuaing habit of 

 Comesperma,the samaroid fruit of 

 Securidaca, and it may even be 

 added, the deleterious qualities of 

 some Polygalas, together with the 

 saponaceous secretions of the 

 Monninas, are all arguments of 

 the strongest kind in favoui* of 

 Milkworts and Soapworts belong- 

 ing to the same Alliance. 



Certain anomalous genera, be- 

 longing as I think to this Order, 

 liave been elevated to the rank of 

 Natural Orders. Of these Trigo- 

 nia, a genus of tropical American 

 trees, has been divided from 

 Milkworts because of its leaves 

 being opposite and having sti- 



Fig. CCLXIII. 



Pig. CCLXIII. — Trigonia crotonoides.— ^. de St. Hilaire. 1. 

 corolla, with the petals displayed in their natural position; 3. a 

 6. cross section of a seed. 



a flower seen from the side ; 2. tht 

 pistil ; 4. cross section of the ovary 



