254 



PRINCIPLES OF PLANT-TERATOLOGY. 



Mimulus luteus var. was correlated with the petaloid 

 development of the calyx. In the goldielocks-bnttercnp 

 (Ranunculus auricomus) the corolla, either wholly or in 

 part, disappears. Velenovsky found individual plants 

 of R. acer in which the stamens were absent or abortive, 

 this feature being accompanied by a tendency to 

 abortion in the corolla. In the chick weed (Stellaria 

 media) and the mouse-ear (Cevastium vnlgatum) 

 apetalous flowers sometimes occur, while this is the 

 normal condition in a species of pearlwort (Sagina 

 apetala) of the same order. 



In the flowers observed by Prillieux and Stenzel in 

 orchids the 1-mery involved suppression of certain 

 petals ; this was also the case with the labellum in the 

 flower of Cypripedium Selligerum figured. In the flower 

 of Cypripedium superbiens before-mentioned the fusion 

 of the lateral petals with the posterior sepal to form a 

 single large threefold leaf involved complete suppres- 

 sion of the labellum, an interesting example of how 

 the law of alternation works. 



Wakker found and figured a flower of the toadflax 

 (Linavia vulgaris) whose corolla was quite normal 

 except for the complete absence of a spur ; this fact 

 was due to the middle petal (not middle lobe only, 

 as some systematists would assert), i. e. the median 

 anterior one, being absent ; for in these plants the spur 

 is an outgrowth of this petal. In conformity herewith 

 there were only four sepals ; and it would probably be 

 found (the author does not inform us further) that the 

 reduction in this whorl, in accordance with the usual 

 working of the law of alternation, was due to fusion 

 of the two lateral anterior sepals to form a single one 

 inserted opposite the gap left by the median anterior 

 petal. 



3. Stamens. — Synandry. — Andersson observed fusion 

 of the two stamens in Salix calyculata ; and this is a 

 normal feature in 8. monandra, and precisely simulates 

 the normal union of the two carpels to form the syn- 

 carpous ovary. A similar kind of union occurs normally 



