April, 1921] 



Reversal of the Sexual State 



187 



fact that in the Anthophyta bisporangiate flowers have their 

 stamens below and their carpels above. The reason for this 

 may be that in the comparatively long axis of the inflorescence 

 the outer, later end may usually be in a much less favorable or 

 at least different condition functionally than the lower part, 

 while in the evolution of the flower, the two parts of the flower 

 axis may be more alike or the upper part even better placed for 

 favorable metabolism than the lower part. At least there are 

 strobili and flow^ers which plainly show a crowding on the lower 

 part of the axis. 



Below are given lists of common plants in which a complete 

 change from one sexual state to the other takes place in the 

 inflorescence. Besides the examples of a change from carpellate 

 to staminate or from staminate to carpellate, a few special 

 cases are also cataloged, the most significant of which appear to 

 the writer to be the inflorescences that change from bisporangiate 

 flowers below to staminate flowers above. 



INFLORESCENCES WHICH ARE CARPELLATE BELOW AND 



STAMINATE ABOVE. 



Sagittaria latifolia Willd. 



Sagittaria rigida Pursh. 



And other species of Sagittaria. 



Sparganinm eurycarpum Engelm. 



And other species of Sparganinm. 



Typha latifolia L. 



Typha angustifolia L. 



Peltandra virginica (L.) Kunth. 



Zantedeschia aethiopica Spreng. 



Arisaema dracontinm (L.) Schott. 

 Monecious individuals. 



CymophyUus fraseri (Andr.) Mack. 



Car ex nardina Fries. 



Carex capitata L. 



Car ex gynoc rates Wormsk. 



Carex chordorrhiza Ehrh. 



Carex arenaria L. 



Carex leavenworthii Dew. 



Carex cephaloidea Dew. 



Carex jamesii Schw. 



Carex leptalea Wahl. 



Carex rupestris All. 



Carex lacustris Willd. Carpellate spike- 

 lets below, staminate above. 

 Many other species of Carex. 



Carex liipulina Muhl. Several carpel- 

 late spikelets below; one staminate 

 spikelet above. 



Other species of Carex. 



Zizaniopsis miliacea (IMx.) D. & A. 



Tripsacum dactyloides L. 



Miisa sapientum L. 



Stillingia sylvatica L. 



Cnidoscolus stimulosus (Mx.) Engelm. 



and Gr. 

 Acalypha virginica L. 

 Tragia urens L. 

 Tragia nepetaefolia Cav. 

 Tragia ramosa Torr. 

 Tragia macrocarpa Willd. 

 Ditaxis mercurialina (Nutt.) Coult. 

 Croton glandulosiis L. 

 Pachysandra procumbens Mx. 

 Myriophyllum spicatum L. 

 Myriophyllum heterophylliim Mx, 



And other species of Myriophyllum. 

 Ambrosia trifida L. 



And other species of Ambrosia. 

 Gaertneria acanthicarpa (Hook.) Britt. 

 Gaertneria discolor (Nutt.) Ktz. 

 Gaertneria tomentosa (Gr.) Ktz. 

 Xanthiitm spinosnm L. 

 Xanthium peyinsylvaniciim L. 

 Polymnia uvedalia L. 

 Polymnia canadensis L. 

 Silphmni perfoliatiun L. 

 Silphium integrifolium Mx. 



Other species of Silphium. 

 Artemisia caudata Mx. 



And some other species of Artemisia. 



