Amphicarpcea monoica. ^5' 



produces a distinct type of fruit. The atrial flower has a 

 papilionaceous corolla, the subterranean is apetalous. 6 

 The atrial flower never matures a legume similar to that 

 resulting from the subterranean flower; but there exists no 

 record of experimental evidence regarding the behavior of 

 cither flower, if compelled to develop in a manner differing 

 from that which is considered normal. 



Arachis hypogcea has recently been studied by Mr>. 

 Pettit."' Arachis bears practically but one kind of flower, 

 which is usually found above ground, though occasionally 

 specimens have been seen upon the subterranean portion of 

 the stem. The flowers occur singly in the axils of the 

 leaves, and are sessile. After fertilization, the floral parts 

 fall, the gynophore lengthens and exhibits a decided geo- 

 tropic tendency. Growth continues until the ovary is 

 carried underground. This process is aided by the de- 

 velopment of a brown hardened tip upon the ovary. If 

 from any cause the ovary is prevented from entering the 

 soil, no fruit results. This statement is verified by experi- 

 ments conducted by M. Correa de Mello.- 4 No differences in 

 character have been observed in the fruit resulting from 

 the subterranean flower. Mrs. Pettit observed the devel- 

 opment of a zone of hairs upon the gynophore after its 

 entrance into the soil ; these hairs also developed where 

 the gynophores were placed in moist chambers. After a 

 series of experiments, she decided that their probable func- 

 tion is to assist in absorbing nourishment for the maturing 

 fruit. 



In marked contrast to all of these plants, stands Amphi- 

 carpcea with its three distinct types of flower and fruit 

 occurring in a season. We have here a series of great 

 value, as study of the structural pecularities shows a 

 gradual transition from the aerial to the subterranean form. 

 It is worthy of attention, too, that the aerial apetalous 

 flower in the upper part of the plant may be forced to de- 

 velop a fruit and seed of the subterranean type, provided 

 the flower or a young legume is placed under the proper 



