Ill 



passing through the openings in question, and connecting the 

 like tissues of the normal and anomalous formations, this is 

 not in the same degree the case with lodes tomentella ; for, as we 

 have seen , the openings o o PI. XVIII , Fig. 4 are chiefly filled 

 with secondary parenchyma. There are however in this paren- 

 chyma a few scattered sieve-tubes which run from the normal 

 secondary bast obliquely inwards and downwards through the 

 openings in the vascular ring, and, on reaching the pith, join 

 themselves to the sieve-tubes of the anomalous phloem, thus 

 effecting a more or less perfect communication between the 

 two tissues. 



Before leaving lodes tomentella, a few words may be said of 

 its not uninteresting morphology. It is characteristic of all the 

 Phi/tocreneae , which I have seen, that they have in or rather 

 over the axil of each leaf several buds, most of which are 

 abortive. In other families where a number of buds occur in 

 or over the axil , the development , with few exceptions , is 

 acropetal, the lowest bud developing first and strongest, and 

 so far as 1 am able to learn the only exceptions in literature ^) 

 to this rule are Aristolochia Clematites , Gymnocladus canadensis 

 and the germinating Juglans regia. The Vhytocreneae , as I find, 

 furnish several further excellent examples of the unusual ba- 

 sipetal development in supernumerary buds , namely Phytocrene 

 macrophylla , lodes tomentella , /. ovalis , Natiatum herpeticum and 

 Pyrenacantha scandens. In lodes tomentella the number of these 

 buds although always definite is not the same for different 

 axils. The leaves , as already mentioned , are opposite , and the 

 axil of one of the leaves at each node contains three buds of 

 which the upper one developes regularly to a branch , while 

 the others are aborted. In the axil of the opposite leaf how- 

 ever there are but two buds, neither of which developes. The 

 bud which gives rise to the branch appears therefore to have 



1) Cf. Irmisch, »Ueber einige Pflanzen bei denen in tier Achsel bestimmter 

 Blatter eine ungewohnlich grosse Anzahl vou Sprossanlagen sich bildet." Abhandl. 

 d. Natw. Ver. z. Bremen 1875. 



Goebel, Entwicklungsgesch. d. Pflanzenorgane p. 197, Schenk's Handbnch. 

 Ann. Jard. Buit. Vol. VIII. 8 



