MORPHOLOGICAL AND ANATOMICAL STUDIES OF 



THE VEGETATIVE ORGANS OF RHEXIA 



/- Theo, Holm 



(with plates I AND II) 



An anatomical classification of the Melastomaccae has been pro- 



int 



n ■ 



Melastomeae and Memecyleae. In the former 



:ondary 



p ri 



^ « ■ \ i 



B groups of leptome m as many concentric bands as 



_ _ Ik 



the stem shows annualrings. The Melastomeae comprise four sub- 

 tribes: Dermomyelodesmeae, with supernumerary mestome strands 

 in the cortex and pith; Dermodesmeae, with supernumerary mestome 



r 



r 



strands in the cortex alone; Myelodesmeae, with supernumerary 



■ 



mestome strands in the pith alone; and Adesmeae, without super- 

 numerary mestome strands. The Memecyleae comprise two sub- 

 tribes : Pternandreae, without sclereids in the leaves ; and Mouririeae, 

 with sclereids in the leaves. The genus Rhexia belongs to the Der- 

 momyelodesmeae. 



Among other anatomical works may be mentioned those by 

 Pplaum/ Palezieux,^ and Vochting/ and also a very detailed 



diagnosis of the family in Solereber's Systematische Anatomie der 

 Dicotyledonen (p. 405). 



It would thus appear as if the family had already been treated 

 to such an extent that little if anything of real importance could be 

 addedj a fact fully appreciated by the author. However, the study 

 of internal structure is not always accompanied by a corresponding 

 treatment of the external^ and so far the Melastomaccae have not 



1 Classification anatomique des Melastomacees. Bull. Soc. Bot. France 38: 

 114, 1891, 



2 Anatom.-systemat. Untersuch. d. Blattes der Melastomaceen. Diss. Munchen, 

 1897. 



3 Anatom.-systemat. Untersuch. d, Blattes der Melastomaceen, Bull. Herb. 

 Boiss. 7: appendix v. 1899. 



4 Der Bau und die Entwickelung des Stammes der Melastomaceen. Hanstein's 

 Bot. Abhdl. 3:1. 1878. 



Botanical Gazette, vol, 44] [22 



