GLEASON: CENTROPOGON AND SIPHOCAMPYLUS 191 
elongation of the internodes and better development of the sub- 
tending leaves is reduced to a series of solitary axillary flowers. 
The hypanthium, varying from depressed hemispheric to cylindric, 
bears five sepals, ranging from a size approximating the length 
of the corolla-tube to almost suppressed. The large corolla is 
usually brightly colored, with five equal or unequal, long or short, 
spreading, erect, or depressed lobes. The filaments usually surpass 
the corolla, and the anther-tube is frequently hirsute; in almost 
all species the two anterior anthers bear an appendage or tuft of 
hairs at the apex. The foliage is in some cases glabrous, but in 
most species is pubescent to tomentose with simple, branched 
or stellate hairs. 
The distinctions between Centropogon and Siphocampylus are 
difficult and in herbarium material frequently obscure or lacking; 
as a result, sheets of what is obviously one species have been 
classified by Zahlbruckner himself in both genera. In Centropogon 
the fruit is a dry or leathery indehiscent berry. This flattens out 
in pressing and is thin enough to show the impression of the small 
seeds within. In Siphocampylus the fruit is a stiff, firm-walled 
capsule, but in many or even most herbarium sheets available 
mature fruit isnot athand. In the former genus, also, the summit 
of the ovary is described as truncate, that is, as almost completely 
adnate to the hypanthium, while in the latter it is stated to be 
conical, with a free distal portion, and adnate to the hypanthium 
only at its base. This condition does obtain in the ripened 
fruit, but can not always be demonstrated in flower. Between 
the baccate and the capsular species there is extensive parallelism ; 
so extensive that a doubt may legitimately arise whether the 
characters of the fruit are really of generic value. 
Because of this parallelism, the species of the two genera have 
not been kept separate in this paper but have been keyed out side 
by side, using the shape of the corolla as the primary distinction 
between groups. Three such groups have been distinguished, 
of which one includes only species of Centropogon (in the usual 
sense), the second only species of Siphocampylus, and the third 
species of both genera. To obviate the necessity of descriptions, 
the analytical key has been made more detailed than necessary 
for the mere separation of the species. 
