FLORAL ANATOMY ОЕ SOME COMPOSITÆ. 521 
Considering now the anatomy of the bilabiate florets in Tussilago Farfara, 
we find the same primary bundle as in Senecio vulgaris and Taraxacum 
officinale (fig. 4, diag. 1) and the same lower distributive centre (fig. 4, 
diag. 2). The bundle at this stage in 7. Farfara is more clearly defined 
than in the other cases, being a well-marked disc from the interior of which 
arise five strands, four to supply the periphery of the ovary and the fifth to 
supply the ovule (fig. 4, diags. 3 & 4). The anterior bundle is usually 
larger than the others, even at this stage. There is some variation in the 
number of the peripheral bundles, five occurring frequently and the number 
may increase to six, seven, or eight. АП these fuse at the upper distributive 
centre, and above that point four is the constant number. The upper 
distributive centre is clearer and shows more symmetry than in the other 
species examined. ‘There are two well-defined ares with the lateral bundles 
in the centres of the ares ; these two arcs are joined at their anterior and 
posterior ends by two shorter ares with arms forming sectors (fig. 4, diag. 5). 
From the points of the sectors arise the two stylar bundles (fig. 4, diag. 6). 
At this stage the somewhat rudimentary pappus shows many interesting 
stages in the “splitting ” of this solid ring of tissue into the numerous hairs 
of the mature pappus, which are multicellular at their bases, but split higher 
up into hairs which are unicellular in cross-section. The pappus has no 
vascular supply. 
The posterior bundle soon comes to an end, and the corolla remains a tube 
with three conducting strands (fig. 4, diag. 7). The lateral strands continue 
in a very attenuated form, supplying the margins of the corolla after the 
tube splits to give a distinct lip (fig. 4, diag. 8)*. The style remains 
unbranched up to this point, but higher up it branches and the conducting 
strands become merged in the elongated cells of the layer below the stigmatic 
papille (fig. 4, diag. 9). Beyond the style the lip becomes flattened (fig. 4, 
diag. 10), and the anterior bundle extends almost to the tip of the corolla. 
The cells lining the stylar canal become lignified ; the stylar canal is burst 
on the anterior and posterior sides by the developing embryo and the 
lignified cells persist after the degeneration of the surrounding parenchyma, 
forming two secondary conducting strands one on each side of the embryo 
(fig. 4, diag. 3). These strands are more conspicuous in this species than 
in most, and Brown (2, p. 89) mentions Tussilago odorata + as another 
species in which these “ cords” are easily separable from the “ ovarium.” 
Fig. 3 shows the complete vascular system, and ‘this figure and the 
diagrams of fig. 4 are arranged so that the posterior side is at the left 
as in figs. 1 & 2. 
# In the few cases where there are two main bundles in the anterior lip, one of these is 
shown by the examination of serial sections to be an abnormally well-developed lateral 
bundle and the symmetry in the corolla-tube is of the usual form. 
+ Piobably Petasites fragrans, Presl. . 
