STRUCTURE.] OF TURNERADS. 39 



Another very curious fact confirms this idea ; of the many 

 ovules found on each placenta, there are very few that arrive 

 at maturity, the rest become early abortive, but, nevertheless, 

 remain at the side of the ripe seeds ; and, what is a very 

 remarkable fact, even if they are dried and reduced in size as 

 much as possible, their arils for all that become very large 

 sacs. The latter are only a little smaller and not so much 

 cut as the arils of the perfect seeds. This shows that the 

 aril can grow independently of the ovule, just as in some 

 fruits the pericarp continues to grow after the abortion of all 

 the ovules. This observation, which I have made on a 

 Samyda, has also been made by M. Cambessedes on the seeds 

 of Casearia grandiflora. 



Knowing that the aril exists in the Samyds, we shall not 

 be surprised to find it in an allied order, viz., that of 

 Turnerads, where this organ, although it retains its cha- 

 racters, is much modified in form. In a capsule of Turnera, 

 the parietal placentae bear numerous anatropal seeds, which 

 are nearly cylindrical, obtuse at the two ends, and slightly 

 bent. An umbilical cord, which is rather slender, is inserted 

 at a short distance from the micropyle, and gives rise, below 

 its point of attachment, to a sort of membranous, transparent 

 tongue, which applied, but not adhering to the ventral side 

 of the seed, extends more or less according to the species, 

 without reaching either the dorsal side or the base of the seed. 

 Some people, deceived no doubt by an apparent resemblance 

 between this tongue and that found on the seeds of Corydalis, 

 have called the former a Strophiole, whereas this name applies 

 to the latter only. The strophiole, indeed, is an excrescence 

 of the integument, and has nothing to do with either the 

 umbilical cord or with the micropyle ; and I shall show in 

 the sequel that this is the case with the tongue of Corydalis. 

 That of Turnera, 011 the contrary, belongs so little to the 

 integument, that, when the seed is detached from the umbili- 

 cal cord which remains fixed to the placenta, the membranous 

 tongue is often found at the other extremity of the latter, and 

 thus its arillary nature admits of no further doubt. This 

 aril, which covers the seed incompletely, is found throughout 

 the whole of Turnerads, if we can, by analogy, apply what 



