MEMOIRS FROM THE DEPARTMENT OP BOTANY OF COLUMBIA COLLEaS. 11 



nectaries. However, with all this variation and greater or less specialization of organs, 

 there seems to be about as much close as cross-fertilization, and even in the case of 

 species in which cross-fertilization does occur the amount of progeny does not depend 

 upon the cross-fertilization, as has been shown by observation. 



The flowers are apetalous, but the calyx is often highly colored and its segments 

 petaloid. It is always persistent, and is usually accrescent after the flowering stage, so 

 that it invests the achene. Glands are often present in its tissues. It is generally five- 

 cleft or five-parted, although we find it in many cases varying from four to six-cleft or 

 parted. The segments are nearly equal or the outer ones larger and often develop keels 

 or conspicuous wings which invest the fruit. From three to nine stamens are present in 

 the flower; five or eight, however, are the prevailing numbers; they are variously in- 

 serted on the base of the calyx, sometimes accompanied by a corresponding number of 

 nectaries. The ■ filaments range from filiform to subulate or even bottle-shape ; they 

 are persistent and sometimes alternate with small scales, and the oblong or ovoid anthers 

 are attached to these by their backs, the sacs of the latter opening longitudinally. A 

 pistil of variable length surmounts the lenticular or triquetrous ovary, which is one- 

 celled and bears one ovule. The two or three style-segments have usually been con- 

 sidered as so many styles more or less united at the base. In my opinion this is an 

 erroneous -way of interpreting the .morphology. The ovary is one-celled, bears but 

 one ovule, and finally produces a typical achene. So it is more logical to consider the 

 style as simple and more or less cleft or parted. The cases in which division to the base 

 takes place are comparatively few. We should therefore interpret the state of the style 

 as two or three cleft or parted, as the case may be. 



The ovary develops into a lenticular or triquetrous achene. If the style-segments 

 are two the fruit will be lenticular ; if three, triquetrous. I have found a state approach- 

 ing a tetragonous fruit, but have never been able to detect a fourth style-segment. 



The achene is either completely invested by the enlarged and persistent calyx or 

 in a few species conspicuously exserted. It has a coriaceous or membranous peri- 

 carp, which is smooth and shining or granular and dull. The angles of the fruit are 

 sharp or rounded, and its faces concave or convex. A single seed is developed in each 

 achene. This latter is principally made up of horny or mealy albumen, and usually 

 takes the same shape as the pericarp. The embryo is situated in an angle of the albu- 

 men. The cotyledons are slender, foliaceous, accumbent or incumbent. The latter two 

 characters of the embryo vary among the different subgenera, but they are constant 

 in the same subgenus. 



