356 ANTTUAL REPOiRT SMITHSONIAN INSTITUTION, 1942 



constricted and generally covered with tiny peltate scales which serve 

 as "cups." 



In the "style" of leaves there is great diversity in color and form, 

 which makes so many of the bromeliads highly decorative plants even 

 when not in bloom. Spots, horizontal and longitudinal stripes, 

 zigzag mottling and plain green, spiny and perfectly smooth surfaces, 

 are leaf characteristics which, together with a wide range of color from 

 many shades of green and yellow to grays, reds, and maroons, combine 

 to produce the bromeliads' bizarre beauty. Some leaves are coarse and 

 stiff, others are delicately drooping and grasslike. Some leaves are so 

 curled and dried up that they give little appearance of life. The half- 

 inch leaves of Tillandsia trwholepis are indeed dwarfs in comparison 

 to the 9-foot leaves of Streptocalyx -floribunda. 



Wide variation in the size of the bromeliad plants is well illustrated 

 even within the genus Tillandsia by the tiny 1-inch Tillandsia loliacea 

 and the huge Tillandsia grandis of Mexico which shoots a branched 

 inflorescence 11 feet high. 



Most of the bromeliads have roots, but in many species these no 

 longer function as feeders. The ability to feed through the leaves is 

 particularly emphasized in the epiphytic types. Tillandsia usneoides 

 (Spanish moss) and Tillandsia decomposlta thrive, although entirely 

 lacking in so fundamental a part as roots. Tillandsia usneoides seems 

 to have merged the roots with the leaves, both in function and in ap- 

 pearance. Tillandsia decomposlta of Matto Grosso develops a few 

 roots in infancy and then dispenses with them and matures with the 

 leaves tenaciously curled around the twigs within its octopuslike grasp. 



However, most epiphytic types retain enough roots to serve as a 

 brace to hold the plant either in an upright position so as to catch the 

 rainfall or in a downward position (as we found them in high, cold 

 Mexican climates), so as not to hold the water which might freeze 

 between the leaves. This method of clinging to trees has been the cause 

 of the mistaken viewpoint that these epiphytes are parasitic. They 

 actually take no substance from the trees to which they cling. They 

 need only a position where they will get adequate aeration and where 

 they will be able to catch the rainfall as well as the falling leaves from 

 trees above, which decompose into a vegetable "tea" m the "cup" of 

 water. This is the food taken in by the leaves, a process that eliminates 

 the age-old plant habit of feeding through the roots. It may be con- 

 jectured that at the remote period when the first terrestrial bromeliads 

 were developing, they encountered the choking, dark, overcrowded 

 jungles. For survival they took to the trees, where they lost most of 

 the feeder function of their roots. 



Yet it is interesting to see how quickly the hold-fast roots of the 

 epiphytes can be converted to function more as feeder roots. In a 

 greenhouse the roots of a ]3otted bromeliad function as feeders and 



