GYMNOLOMIA TORTERI. STONE-MOUNTAIN STAR. I 39 



The generic name Gymnoiomia, which, as we liavc before 

 noted, was given to certain South American species in 1S20 

 by Humboldt and his associates, is doubtless derived from two 

 Greek words, signifying " a naked border," and refers, perhaps, 

 to the circumstance that the florets have no pappus or calyx, 

 either in the shape of bristles or scaly appendages, on tlie sum- 

 mit of the achene (see Fig. 2), beneath the corolla. 



In the Gymnolomia Portcri the receptacle is jDrovided with 

 scales, — one scale for each floret; and although this is rather a 

 common character in the plants belonging to the Composites, 

 and especially in the allies of the present species, the nature of 

 the scales in our plant is, nevertheless, worth noting. As a 

 general rule, these scales are chaffy and almost colorless, while 

 in the Gymnolomia Portcri, as shown in our Fig. 2, they are 

 colored ; and this gives a chance to the student to trace their 

 relationship to the involucral scales, and through them to the 

 leaves, and at the same time offers a clew to the true relation- 

 ship of the Composites to other classes of plants. A few 

 moments' consideration will convince us that all plants, the 

 Composites included, are formed upon one primordial plan, 

 which plan is simply modified by the laws of acceleration or 

 retardation. Let us imagine that all flowers proceed from axial 

 buds, or, in other w^ords, from the bases of the leaves, above 

 the connection of these latter with the stem or axis, each bud 

 having its own leaf to start from. Usually, the stem is length- 

 ened, or, as we say, accelerated in its growth, so that the leaves 

 are scattered upon it, each one being situated at some distance 

 from its next neighbor. In such a case, the flowers are, of course, 

 also scattered along the stem, and, from their })osition in the a\ils 

 of the leaves, they are said to be axillary. But if we now suppose 

 this growth of the stem to be suddenly checked, so that the 

 distances between the various leaves are considerably diminished, 

 and the leaves themselves stunted in their orrowth, we shall have 

 the flowers in a raceme; and if we continue this diminishing pro- 

 cess still further, until the stem is so reduced that the flowers are 



