1963] 



BOTANY OF THE QUAY AN A HIGHLANDS PART V 



195 



Dendrosipanea Ducke, Arch. Inst. Biol. Yeg. Rio de Janeiro 2 : 69. 1935. 



This genus, a member of the tribe Rondeletieae, was established by Dncke in 

 1935 based on D. spigelioides Dncke collected from the state of Amazonas, Brazil 

 (ad ripas inundatas fluminis Cnricuriary affluent is Rio Negro superioris). When 

 he described this genus, Ducke believed that its closest allies were Ucriana and 

 Sipanea, both of which genera have loculieidally dehiscent capsules. In his 

 original description of the genus Ducke (loc. cit. pp. 69-70) states that the 

 capsule "ab apice loculicide dehiscens," but an examination of mature fruiting 

 capsules of an isotype specimen at NY (Ducke 24426) shows indubitably that 

 the dehiscence is septicidal. 



The septicidal type of dehiscence is further demonstrated by the collection 

 of Maguire, 'Wurdack, &' Bunting 37592, the holotype of one of the new species 

 of this genus described below. The small, angled, many-sided scrobiculate seeds 

 of the Maguire, Wurdack, & Bunting collection are obviously of the same type as 

 and congeneric with those of D. spigelioides. 



The relationship of Dendrosipanea, because of its septicidal type of dehiscence, 

 is much closer to the genus Chalepophyllum, discussed in another section of this 

 paper, than with any other genus. The main differences between the two genera 

 are to be found in the type of inflorescence, character of seeds, ornamentation 

 of the lower surface of the leafblades, stipules, and amount of viscous exudation 

 of the upper nodes of the branches. These differences may be expressed in the 

 following key : 



. 1. Seeds narrowly winged or margined, compressed, the testa spongy-foveolate, 2.8-4 

 mm "long, the body contour evident by the constricted margins; stipule inconspic- 

 uous, low, broadly triangular, barely acute, not bifid; inflorescence axillary, of 

 solitary flowers or cymosely grouped 2-4 together at the ends of short or elongated 

 peduncles; veins on lower surface of leaf-blades prominently elevated to form a 

 tessellated rugulose areolate surface; glutinous exudate abundant and obvious in 

 uppermost parts of the branches ;it the base of the petioles, pedicels, or peduncles. 



Ch ale po pity Hum. 



1. Seeds neither alate nor margined, angled, many-faced, not compressed, the testa 

 finely scrobiculate, 1-1.8 mm long, the body contour not evident; stipules conspic- 

 uous, becoming acuminate and often bifid; inflorescence terminal in a many-flowered 

 usually trichotomous cincinnate cyme; lower surface of leaf-blade not tessellate- 

 areolate, the veins not elevated; glutinous exudate of branches lacking or incon- 

 spicuous. Dendrosipanea. 



The new collections of Dendrosipanea by Maguire and Wurdack and their 

 associates, especially those assigned to the new species, D. revoluta, demonstrate 

 the close affinities between Dendrosipanea and Chalepophyllum, but the two 

 genera may be distinguished on the basis of the differences outlined above. 



In view of the erroneous original description of the mode of dehiscence of the 

 fruit by Ducke, it is necessary to emend the description as follows : 



Dendrosipanea Ducke emendavit Steyermark 

 Capsula ab apice septicidali dehiscens. 



Shrubs or small trees. Stipules interpetiolar, entire to bifid with a pronounced 

 acute to acuminate apex, mainly persistent. Leaves opposite, petiolate. Inflores- 

 cence many-flowered, terminal, trichotomously branched into a cincinnate cyme. 

 Bracts of inflorescence inconspicuous, subtending short pedicels. Calyx-lobes 5, 

 persistent, equal or unequal. Calyx-tube (hypanthium) turbinate. Corolla white, 

 hypocrateriform, the tube elongated-cylindrical, densely yellow-barbate in throat, 



