ON CERTAIN EPIGYNOUS MONOCOTYLEDONS. 165 



cipal spiral. This small bract may be regarded, as in the Can- 

 naceae, as belonging to another suppressed flower, and it is con- 

 sequently analogous to the two little bracts which we find at 

 the base of the flowers in so many Dicotyledons. This frequent 

 supposition of flowers without bracts, and involucral bracts [deck- 

 bldttern) without flowers, would not be justifiable, were not such 

 conditions more clearly exhibited, for example, in Alpinia nutans 

 or racemosa. Moreover, we continually meet with one or other 

 in the Cyperaceae, Grasses, Bromeliaceae, and many other 

 plants. 



The mode of composition of the spikes of a Costus is un- 

 usually favourable to organogenetic investigation. If we select a 

 spike not too old, we may trace all the stages from the dehiscent 

 fruit to the bud forming merely a milky papilla behind its 

 bract. In this young condition I never could detect a bract at 

 the side of the bud, but it was distinctly visible by the time the 

 bud approached the form of a nodule. This nodule then began 

 to exhibit an excavation in its upper surface and towards the 

 large bract. Next, in the middle of this excavation appeared 

 another papilla which also soon became concave ; the sepals then 

 began to separate distinctly, at least the two standing on the 

 side next the axis. The cavity formed by the second circle of 

 organs is at first of longish-round, but soon passes into a trian- 

 gular shape. Thereupon three symmetrically arranged furrows 

 show themselves between this excavation and the outer border of 

 this circle, one behind each of the sides of the triangular excava- 

 tion, while a little depression is observed at the place where the 

 middle lobe of the labellum is to appear. The said furrows quickly 

 run together and coalesce, so that soon afterwards the anther 

 and the labellum with its three lobes are distinctly indicated. 

 The two additional segments of the sides of the labellum make 

 their appearance somewhat later, when the labellum, which for 

 a short time forms with the anther a circular ridge in the inte- 

 rior of the flower, interrupted only by the middle lobe, separates 

 and proceeds independently in its development. If w^e open a 

 rather older flower, we find all five lobes of the labellum already 

 developed, and the furrows of the anther also becoming evident. 



The stigma deserves especial attention. It is first observed 

 at the bottom of the flower, as a little, somewhat flattened ele- 



