62 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 10 



tudinal slits in Marlierea. These two genera were early recognized as distind 

 from Myrcia (including Aulomyrcia) which possesses we'll -formed, separate and 

 usually markedly imbricate calyx-lobes which are persist ent and do not split 

 irregularly in the sinuses. At the time of Berg's monumental revisions of Ameri- 

 can Myrtaceae (1805-1859) he knew a total of 69 species of Calyptranthes and 

 29 species of Marlierea, all of which were reasonably well set off from the 424 

 species of Myrcia- Aulomyrcia which he recognized. As more material has be- 

 come available, however, particularly from northern South America, it has 

 become increasingly apparent that the generic lines in the Myrciinae (the sub- 

 tribe which includes the genera just discussed) are not entirely sharp. 



A majority of the species of Myrcia have well-formed calyx-lobes which 

 change little from the flowering to tin 1 fruiting condition ; the lobes are usually 

 broadly rounded, markedly imbricate in bud and in flower, and scarcely sepa- 

 rated at base even in fruit; the hypanthium may or may not be prolonged into 

 a cuplike or cylindric structure which surmounts the ovary and the fruit, the 

 distal margin of the hypanthium rarely splits between the calyx-lobes, and the 

 structure as a whole often persists as a short cylinder with nearly parallel sides, 

 terminating in the spreading calyx-lobes. 



In Calyptranthes the buds are completely closed and often apiculate, open- 

 ing by a calyptra which usually remains attached by a narrow band of tissue at 

 one side. Dehiscence of the calyptra follows a line parallel to the line of inser- 

 tion of the stamens, and just above this line. 



In the original species of Marlierea the buds are closed and apiculate as in 

 Calyptranthes, or in a few species barely open at the tips, with very short and 

 imperfectly developed calyx-lobes. The buds open by four or five irregular 

 longitudinal slits which extend from the tip of the bud down at least to the 

 distal margin of the zone of insertion of the stamens and sometimes well into 

 or beyond this zone. The irregularly shaped 'calyx-lobes" which result from 

 this splitting probably include in every instance the tip of the calyx proper, 

 and at the base a portion of the hypanthium. In many species there is evident, 

 in addition to the splitting of the hypanthium, a tendency for this structure to 

 become explanate : the tube of the hypanthium, which in flower is regularly 

 much prolonged beyond the summit of the ovary (i.e. beyond the level at which 

 the style arises) becomes flattened or merely somewhat concave at the center, 

 and the irregular lobes widely spreading or reflexed, and often ultimately 

 deciduous. 



These differences may be summarized as follows : 



Lobes separate Calyx 





Calyx (bud) 



Lobes 



Hypanthium 



in fruit 



Persistent 



■ 



Myrcia 



Open : 



as in bud 



Not splitting 



No 



Yes 





I )ist inet 













lobes 











Marlierea 



Closed 



irregular 



Splitting 



Yes or decidu- 



Weakly 





or minute 



after 



Explanate 



ous 







lobes 



splitting 









Calyptranthes 



Closed 



None 



Not splitting 





( Jalyptra 







(calyptra) 



Tubular 





sometimes 



