ANALOGY OF PLANT ORGANS. 67 



a:n"alogy. 



Having now considered the Homology of the different pLant- 

 org-aiis, and the various functions each may sustain, we may collect 

 tinder dilt'crent heads tlie functions which various organs possess in 

 common. In other words, such lists will exemplify the data upon 

 which the possibility of Analogy of plant-organs exists, irrespective 

 of their origin. Though, we must remember that all those of each 

 group which are (on the one hand) axial or caulomes, as well as 

 (on the other) all organs that are phyllomes, will be, respectively, 

 homologous. 



I. Keservoies of Nutriment. 

 Caulomes : — 



1. Koots, tuberous — Dahlia, Paonia. 



2. Stems, subterranean — Tabers, Corms, etc. 



,, aerial — Sagas, Saccharum, etc. 

 ,, medullary rays — Exogenous wood. 

 Radicle and root — Biennial tap-roots. 



3. Branch — Vitis gongyloides. 



4. General receptacles — Composifce, e.g. Artieholce. 



5. Floral receptacles — Fig and Hose. 



6. Receptacular tube — Apple. 



7. Appendix of spadix — Arum maculatum. 

 Phyllomes : — 



1. Leaf-scales — Bulbs. 



2. Leaf -petiole — O.valis, Aucuba, etc. 



3. Leaf -blade — Bryophyllum calycinum. 



4. Bracts — Artichoke. 



5. Calyx — Mulberry. 



6. Perianth — Pine-apple. 



7. Corolla — Bassia. 



8. Pericarp — Plum. 



9. Testa — Currant. 



10. Albumen — Cotyledons and radicles. 



II. Assimilative Organs. 



All green parts generally possess the power of assimilation, and 

 may be enumerated as follows: — 1, («) young stems containing 

 chloro])hyll, {I) foliaceous stems of ('actus, Euphorbia, Ruscus, etc. ; 

 2, stipu.es {Pisum) ; 3, petioles, as phyllodes {Acacia) ; 4, blades ; 

 5, green bracts; 6, sepals ; 7, carpels and ovules. 



III. PtEPRODUCTm; Ohgans. 



Vcgctatire multiplication may take place on (1) caulomes and 

 (2) phylh>mes : — 

 (1) 1. Roots — Prtmus, Auctiba Japonica, iiic. 



2 Subterranean stems — linlbih, tubers, corms, etc. 



3. Aerial stems — Offsets, runners, aerial bulbs. 



■i. ,, branches — Vitis yongyloides. 



