324 CAIN, DE OLIVEIRA CASTRO, PIRES, AND DA SILVA 



Table 24. Composition and structure of the natural forest of the Horta Botdnico 

 do Instituto Agronomico do Sid, Pelotas, Rio Grande do Sul. Species are arranged 

 by strata, life-form,^ and leaf-size classes}' with a distinction between those more 

 and those less important. Basic data by Dr. Jose da Costa Sacco, with the assistance 



of the authors {Cont.) 



Life form Leaf size 

 G. Vasctdar epiphytes, listed according to the highest stratum 

 attained 



A stratum 



Aechmea legrelliana Baker Bromeliaceae E Ms 



Aechmea gamosepala Wittm. Bromeliaceae E Ms 



Phoradendron sp. Loranthaceae (Hemiparasite) E Mi 



Polypodium vacciniifolium Langsd. & Fisch. Polypodiaceae E Mi 



Tillandsia aeranthos (Loisel) L. B. Smith Bromeliaceae E Mi 



Tillandsia usneoides L. Bromeliaceae E Le 



Rhipsalis aciileata Weber Cactaceae E A 



Rhipsalis sarmentacea Otto & Dietr. Cactaceae E A 



Rhipsalis saglionis Otto Cactaceae E A 



B stratum 



Gen. sp. Orchidaceae E Mi 



Peperomia deppeana Schlecht. & Cham. Piperaceae . E N 



" Symbols used for life-form classes : Ms — Mesophanerophyte ; Mi — Microphan- 

 erophyte; N — Nanophanerophyte; Ch — Chamaephyte; H — Hemicryptophyte; G — 

 Geophyte (Cryptophyte) ; Th — Therophyte; Li — Liana; E — Epiphyte (vascular). 



^ Symbols used for leaf-size classes : Ma — Macrophyll ; Ms — Mesophyll ; Mi — 

 Microphyll; N — Nanophyll; Le — Leptophyll; A — Aphyllus. 



Non-phanerophytic species are mostly associated with margins of the woods 

 and openings or less thick places in it. We made no effort to prepare a list 

 that was typical of the dense woods, but include the entire flora that is 

 typical of the vegetation type as distinct from swamp woods or contiguous 

 grassland. In doing this we believe that the life-form and leaf-size data are 

 fairly comparable with those presented for the rain forest in its more typical 

 forms northward. 



Discussion. In the classification of some species into life-form classes cer- 

 tain problems are encountered. Assignment to phanerophytic-height classes 

 was always made on a basis of the height attained in the stand examined 

 and not on a basis of greater height that might be attained elsewhere. There 

 are some plants that start life as lianas but continue as epiphytes, losing con- 

 tact with the soil, and others starting as epiphytes develop roots that make 

 contact with the soil. In both cases it usually is more accurate to classify 

 the plants as epiphytic. The greatest difficulty is in perennial herbs with 



