98 THE PHENOMENON OF 



sometimes triandrous,* also by the Irideae, Graminacea? 

 and Cyperacea3,t Alisma and Actinocarpus,% Cerastium 

 semidecandrum, and tetrandrum, Mcenchia quaternella, 

 the tetrandrous species of Sayina, the pentagynous 

 Campanulacea?, e. ff., Campanula Medium,^ Drosera,\\ 

 Tamarix^ Viola, &c. On the other hand, an outer 

 circle of stamens is abortive in Triglochin palustre, while 

 in Tr. maritimum both circles are fully developed ; in 

 most of the digynous Solanacese (i. e., with two carpels), 

 in like manner, while in Nicotiana quadrivalvis the fruit 

 becomes four-chambered, by the development of both 

 circles; moreover, in most of the Gentianeae and 

 Apocyneas, the Scrophularinea? and Labiatse, the genera 

 of Rutacese with a double circle of stamens, the digynous 

 and trigynous Alsineae and Silenecs, as well as the penta- 

 gynous genera Malachium and Ayrostemma.** 



An inner circle of stamens vanishes, together with an 

 outer circle of carpels, for instance, in Stellaria media 

 (pentandrd), in most of the Diosmeae, Cneorum, Celas- 

 trineas, Ludwigia, and Isnardia, Circfsa (?),ff Hederaceas, 

 UmbelliferaB, &c. It is probable that in the Polygoneas 

 there is a suppression of 1* to 2 circles of stamens, and 

 one circle of carpels. In Rosaceas, Pomacea3, Arnygda- 

 lineae, Myrtacea3, and Pldladelplius, there is certainly 

 a suppression of several circles of stamens at the transition 

 to the fruit ; probably also we ought to assume two abor- 

 tive circles between the stamen-formation and the fruit 

 in the flowers of the Papilionacea3. A glance back over 



* Juncus sujtinus is ordinarily triandrous, the variety which is held as 

 /. nigritellus, Don, is hexandrous. 



f At least in the Cyperina, the Caricince may be different ; see below. 



Alisma and Actinocarpus are rudimentarily euueandrous, like Butomus. 



\ The suppressed circle of stamens appears developed in the double 

 Campanula Medium of gardens. In this case the first circle of stamens 

 becomes the inner corolla, the abortive circle the circle of stamens. The 

 form and arrangement of the carpels remain unchanged. 



|| Both circles are developed in Drosopfiyllum. 



f[ In Myricaria (Tamarix f/crmanica, L.) both circles are developed. 



** See the 'Flora,' 1843, No. XXII, et son. 



ft See the 'Flora,' 1835, I, 179. 



