APPLICATION OF PHYTOSOCIOLOGICAL TECHNIQUES 319 



portance of hemicryptophytes and the presence of some annuals, along with 

 the reduced importance of phanerophytes. We find also that the mesophyll 

 leaf-size class is no longer the dominant one and that the microphyll class 

 composes 54.3 per cent of all species and 48.6 per cent of all trees and shrubs. 

 There are a few aphyllous species, cacti among the epiphytes and micro- 

 phanerophytes and species of Baccharis among the nanophanerophytes. No 

 sample plots were laid out, and no basal-area measurements were taken. Cov- 

 erage was estimated for natural strata as units, but not for individual species. 

 The woods is penetrated by a rather close network of paths so that access 

 to all parts of it was easy. Table 24 has the species arranged by strata and 

 sub-groups according to relative importance of the species. Further arrange- 

 ment is by leaf-size classes. 



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

 do Instituto Agronomico do Sul, 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 



Life form Leaf size 



A. Tall tree stratum: 15-20 (25) m. Total coverage 50% 



More important species 



Luehea divaricata Mart. & Zucc. Tiliaceae Ms Ms 



Arecastrum romanzoffianum (Cham.) Becc. Palmae .... Ms Ms 



Sorocea illicifolia Miq. Moraceae Ms Ms 



Patagonula americana L. Borraginaceae Ms Mi 



Ficus subtriplhtervia Mart. Moraceae Ms Mi 



Allophylus edulis (St. Hil.) Radlk. Sapindaceae Ms Mi 



Less important species 



Quillaja brasiliensis (St. Hil.) Mart. Rosaceae Ms Mi 



Citharexylum montevidense (Spreng.) Moldenke Verbc- 



naceae Ms Mi 



Xylosma salzmanni Eichl. Flacourtiaceae Ms Mi 



Ocotea pulchella Mart. Lauraceae Ms Mi 



Phyllocalix involucratus (DC). Berg. Myrtaceae Ms Mi 



B. Intermediate tree stratum: (7) 8-10 m. Total coverage 

 70% 



More important species 



Pircunia dioica (L.) Moq. Phytolaccaceae Ms Ms 



Myrsine umbellata Mart. Myrsinaceae Ms Ms 



Pisonia nitida Mart. Nyctaginaceae Ms Ms 



Trichilia catigua A. Juss. Meliaceae Ms Ms 



Maba inconstans (Jacq.) Griseb. Ebenaceae Ms Mi 



