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 is not at hand. 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. 



