274 MESSRS. I. H. BURKILL AND C. H. WRIGHT ON 
a solitary flower; and so on. Further, the axis is peeuliarly 
grooved as the rhachilla of a grass-spikelet, so that the flowers 
fit into the hollow spaces, and the face towards the parent axis is 
much broader than the others. In fig. 4 the position of the flowers 
and their eaducous bracts is marked diagrammatically. It is to 
be noted that no trace of a bract persists where the flower is 
abs. nt. 
lhese are some modifications of the infloreseence which we 
have noted in „Kolanthus. They are of special interest in 
showing an alternation of parts by abortion of one member of 
the pair. We have introduced them here that they may afford a 
contrast between what we see in Zcomum, in zEolanthus, in such 
abnormalities as the condition of Hyptis conferta mentioned above, 
or that of Stachys circinata described by Clos*, and in others 
Where torsion is associated with alternation of the leaves—e. g., 
a Collinsia described by De Vries t. 
Sehlechtendal long ago spoke of the leaves of Labiates as 
pseudo-opposite, meaning thereby tbat there is no connection 
between the two members which oppose one another. Perhaps 
there is something in the idea underlying this. When forsion 
twists the stem of a Labiate the leaves often cease to be opposed, 
those of each pair becoming separated. This is the commoner 
abnormality ; rarer is separation of the leaves without torsion— 
a condition which we see in the Hyptis and Stachys named in the 
last paragraph. Quite another condition is the alternation by 
abortion of one of the paired organs, such as we have seen 
in Molanthus; and distinct again is the alternation which 
apparently has a spiral arrangement, present in Jeomum, in 
the inflorescence of Scutellaria § Heteranthera and in an inter- 
esting abnormality of Physostegia described by P. Duchartre t 
in whieh the number of leaves at a node was multiplied and 
these spread out in a spiral. 
So much for the genera Zcomum and Æolanthus. There 
remains yet to be described a species of the genus Plectranthus, 
in which the leaves are irregularly scattered owing to the unequal 
development of the internodes, and are never truly opposite. 
The aspect of this plant is similar to that which is often met with 
in Linaria vulgaris, Mill., but the 4-lobed ovary and gynobasie 
* “Théorie des Soudures," Ann. Acad. Toulouse, 8me ser, i. 1879, p. 140. 
t “ Bijdragen tot de leer van den klemdraai,” Bot. Jaarboek, 1892, p. 161. 
t Bull. Soc. bot. France, xxxix. 1892, p. 120. 
