68 FLORAL STRUCTURE AND AFFINITIES OF SAPOTACE.E. 



a central tube. These cliamberlets enlarge at the base to form the 

 lateral and outer walls of the ovarian cavity ; but above their 

 cavity is usually more or less effaced. The adult style is, then, 

 traversed by a tube which enlarges into a vault above the free apex 

 of the receptacle, and into this vault the cells of the ovary open at 

 the top. The stigma is usually lobed with as many festoons as 

 there are carpels. In Achras this is masked at anthesis by the 

 copious secretion of viscid fluid. 



The ovules arise singly from the receptacle in front of and free 

 from each carpel at the time when its edges coalesce with its 

 neighbours. Only a single coat is formed, and the nucleus appears 

 to be a lateral outgrowth from the very short funicle or placenta. 

 The micropjie always points downwards and outwards ; and the 

 degree of anatropy is determined by the approach which the inner 

 or receptacular wall of the ovary makes to the vertical. The 

 impression left on my mind was that these organs were the 

 axillary buds of the carpels, — a view that I should not have 

 ventured to j)romulgate had it not been put forward for several 

 other Orders by continental botanists. 



Disk. — In most of the flowers of this order the base of the 

 ovary is more or less thickened and glandular (and hairy.) It 

 secretes nectar in all the species examined fresh, except Bassia 

 and Dasyaulus, where, as is well known, the coroUa-tube is thick, 

 fleshy, and gorged with saccharine juice. In several of the 

 Australian species of Sideroxylon (formerly Achras), the thickening 

 of the ovary forms a well-marked ring above the base, and 

 this is regularly festooned in S. ohdvatum ; hence the autonomy 

 of Hormogijne, founded only on the presence of a disk, supposed 

 to be absent in the rest of the Order, must fall to the ground. 



One or two other points are these : — The pedicels often undergo 

 movements of nutation. They are erect in the bud, pendulous at 

 anthesis, erect again in fruiting. The flower is almost always, if 

 not invariably, proterogynous ; the style is protruded (and the 

 stigma viscid) in the fresh species, before .the corolla has opened 

 anywhere but at the apex. The same relation was noticed by 

 Grifflth and Falconer in Reptonia/' a genus to which to which I 

 shall revert directly. 



It will now be seen that, in all the cases cited, the evolution of 

 the flower is strictly centripetal,! with a tendency to augmentation 

 in the number of parts of the whorl as we advance from the 

 periphery inwards. This would seem to fall under Hofmeister's 

 two great generalizations : — "Each new member arises in front of 

 the widest intervals between the next oldest members." " If the 

 intervals be wide, the new members are formed in front of 

 the intervals between the members of the next oldest whorl 



* In Trans. Linn. Soc, xix., 99, 101. 



+ Variations in the number of parts, reported by other observers, {e.g., ten 

 petals instead of eight, thirteen instead of twelve, Szc), would seem to be due to 

 collateral deduplication. I have been very unfortunate in my search for these 

 abnormalities. 



