356 



METHODS IN PLANT HISTOLOGY 



transverse sections are easily cut. For later stages, the outer part of 

 the spike should be sliced off so that only enough spike is retained to 

 hold the florets in place. 



Prunus and many other members of the Rosaceae furnish examples 

 of the perigynous type of development. In many of them the floral 

 parts do not occur in the usual succession. 



Sepal-\ 

 Bracf- 



--Pefal 

 ■-"Sepal 



Megasporophylls 

 ' (Carpels) 



^JVIicrosporopliylls 

 ■'' fSlamens) 



-Petal 



•Sepal 



'—Brvicf 



jasporophyll 

 XCarpel) 



Megasporangium 

 (Ovule) 



Microsporophyll 

 (Stamen) 

 Microsporangiiim 



\-Petal 

 Sepal 



Petal 

 Sepal'' 



Fig. 125. — Ranunculus acris. floral development. 

 Plant Science (JMcGraw-Hill Book Co., New York). 



X70. From Chamberlain's Elements of 



The epigynous type is well shown in the Compositae. The order of 

 appearance is (1) corolla, (2) stamens, (3) carpels, and (4) calyx 

 (pappus). 



The common dandelion, Taraxacum officinale, affords an excellent 

 series with little labor. Examine vigorous plants which have, as yet, 

 no flowers or buds in sight. Dig up the plant and dissect away the 

 leaves. If there is a white cluster of flower buds, the largest not more 



