774 



and rigidity of the throat of the calyx excercisiug a gradually in- 

 creasing pressure around the upper part of the capsule, and thus 

 causing its separation by the first of the general principles laid 

 down. 



"The author then proceeds to the case of Lecythis, which he thinks 

 is to be explained by the third of his general principles. In illus- 

 tration of this principle he refers to a monstrosity of the common 

 tulip, described and exhibited by himself some years ago at a meet- 

 ing of the British Association. In this monstrosity, the upper leaf, 

 being unusually developed, has cohered by its edges so firmly as to 

 imprison the flower, and this constraint occurring at a period when 

 the stalk was increasing in length, and previous to any consider- 

 able enlargement of the flower-bud, the force applied was chiefly 

 vertical, and has carried off" the upper part of the leaf in the form of 

 a calyptra, leaving the lower part in the shape of a cup, from the 

 centre of which the stem appears to rise. The separation of the lid 

 of the capsule of Lecythis he believes to be effected in an analogous 

 manner ; the septa which form the two or four cells into which the 

 fruit is divided, meet in a thickened axis, and the outer part of the 

 fruit becoming (partly from its natural texture and partly from the 

 adherence of the torus and calyx) hard, solid, and fully grown, while 

 the axis continues slowly to extend, and thus to press upwai'ds that 

 portion of the capsule which rests upon it, causes that portion first to 

 become slightly prominent, and finally by a strain upon the vessels 

 of that particular part, to fall off" in the shape of a lid. In Couroupi- 

 ta the pressure is sufl[icient to mark the surface of the fruit with a pro- 

 minence, but from the partitions giving way early, and from the abun- 

 dant juices produced in the interior, there has not been, he conceives, 

 sufficient pressure to occasion disruption. In all the species of 

 Lecythis, he observes, the extent of the loose cover corresponds with 

 the extent of the axis, and what remains of the latter continues at- 

 tached to it. 



"As regards lomentaceous fruits in general, the author believes that 

 the intervals between the seeds being suflicient to admit of the sides 

 of the fruit cohering (which is promoted in particular instances by 

 special causes), the swelling of the seeds afterwards stretches the parts 

 over them in a degree which this coherence prevents from being 

 equally distributed, drags the tissue forcibly from the junctures which 

 are fixed points, and thus there being a strain in each direction from 

 the middle line of the juncture, the contraction of drying during the 

 ripening of the fi-uit eff'ects the separation. 



