Origin and Development of the Compositee. 127 
mentioned (Chap. V, A), he maintains that a qualitative change has 
taken place and that these “bristle-scales” are “ bristle-scales ” 
not paleae. 
Development. Kraus (V, 44) considered that the foveole was 
epidermal in origin, but Yapp (IV, 98) points out that although the 
ridge is epidermal, the floor of the foveole has a more deeply seated 
origin. The late appearance of the ridge of the foveole and its 
origin from the epidermis is also noted by Martin (II, 47). 
Biology. The arching of the receptacle which occurs in 
Taraxacum and other genera, by means of which the stipitate, 
parachute pappus is accommodated on a more or less hemispherical 
surface, is noted by Benecke (1) and Kronfeld (3). 
B. Variation in the Receptacle. 
Cassini’s analysis of the various forms assumed by the receptacle 
and its appendages is more precise than Bentham’s but the terms 
given by the latter will be used in the following description because 
they are in more general use. 
The receptacle is usually flat or slightly convex, occasionally it 
is conical and more rarely it is concave. This dominance of the 
flat or nearly flat receptacle is explained by the suggested origin of 
the capitulum from a racemose umbel (Chap. VI, B), and it is 
worth noting that Bentham (I, 7, p. 368) regarded the elongated 
conical receptacle as a character of no more than specific value. 
Fig. 20. Receptacle Forms in the Composite . A—scrobiculate; B—foveolate ; 
C—areolate; D—fimbrillate ; E—setiferous (one segment); F—alveolate, 
shallow alveoles with entire margins. 
The surface of the receptacle is described as scrobiculate (Fig, 
20, A) when it is covered with low mounds of tissue with furrows 
between, the top of each mound being occupied by the remains of 
the vascular bundle, which supplied the lower distributive centre 
(cp. II, 63) ; as foveolate (Fig. 20, B) when it is covered with shallow 
circular or polygonal depressions, each with the above-mentioned 
small vascular protuberance; as areolate (Fig. 20, C) when the 
depression is polygonal, more or less flat-bottomed and surrounded 
by a low, narrow ridge ; as fimbrillate (Fig. 20, D) when this ridge 
is higher, with the margin lacerate, denticulate or cut up into a 
