86 Mr. J. Miers on the Tribe Colletiese, 



axis, the cord is thicker and enveloped in a yellowish in- 

 crustation, which, for one-third the length of the seed, there 

 adheres to the outer crustaceous coating, as was observed in 

 Rhamnus chlorophorus. The embryo is perfectly flat ; the coty- 

 ledons very thin and foliaceous, enclosed in an albumen of equal 

 thickness ; the two internal integuments are of extreme tenuity, 

 and on that account are not easily separated. This organization, 

 it will be seen, greatly resembles that of Zizyphus*. 



In Zizyphus, I find the course of the raphe also peripherical, 

 but it runs along the lateral edges opposite the margins of the 

 cotyledons, as in the Colletiea ; and we find here some points of 

 structure deserving of being recorded. The outer corneous 

 covering of the seed is entire, as in the Colletiete, but much 

 thinner in texture, and more translucent. This coating is of a 

 more compressed form, tapering towards the base, which is 

 polished and somewhat tumescent, and which has a basal chink 

 similar to that of the Colletiea, through which the nourishing 

 vessels of the raphe pass from the placenta. It may here be 

 observed, that in the bottom of each cell of the nut is seen a 

 small fleshy cup, with a crenulate raised border, within which the 

 seed is seated, and across the bottom of this cup is a white raised 

 line, corresponding to the hollow in the basal chink of the seed ; 

 but the margins of this chink and the tumid base of the external 

 coating are highly polished, and the latter shows no sign of any 

 organic connexion with the cup : the hilar point of attachment 

 is therefore confined to the mere cord of vessels proceeding from 

 the placenta to the raphe. The second tunic, which is very thin 

 and membranaceous, does not quite fill the cavity of the outer 

 shell; it is more conical at its base, where it terminates in a 

 short thread that issues through the chink above mentioned ; 

 the space between it and the outer shell is filled with a quantity 

 of very lax white cellular tissue ; it is pyriform in shape, much 

 compressed, and tapers into a short cord at its base, which is 

 seen to divide itself into two prominent threads that run along 

 the margins of the tunic, and meet over a large fleshy chalaza- 

 like disk in the apex, in one uninterrupted line : this cord of 

 vessels is therefore completely peripherical, as in Colletia. This 

 second tunic is quite free from a third, inner integument, which 

 is thicker and more opaque, and which invests a very thin fleshy 

 albumen : this third integument is sensibly shorter, and more 

 conical at its base, where it terminates in a dark areolar neck, 

 and tapers into a short suspensor-like thread, which is embraced 

 by the neck of the second tunic. These two integuments are 

 easily separable from one another by the introduction of a needle 



* This structure will be fully shown in plate 33 D of the ' Contributions 

 to Botany.' 



