The Water-Storing Bracts of Mendoncia coccinea 

 Veil, of Brazil 



John W. Hafshberger 



Mendoncia is a genus of the family AcantJiaceae, the twenty 

 species of which are found in tropical America principally in 

 Brazil, Guiana, Peru and an outlying species, M . costaricana 

 Oerst. in Costa Rica. The plants of the genus are shrubs, or 

 vines, usually well-provided with a hairy covering. The sim- 

 ple leaves are opposite and the floral bracts are likewise with 

 their edges adherent. Each pair of opposite bracts usually 

 encloses a single flower, while a few supernumerary buds re- 

 main of small size at the base of each flower. The flowers are 

 trumpet-shaped with a calyx of reduced size and a corolla of 

 five spreading petals inclosing four stamens. The fruit is drupe- 

 like with fleshy pericarp and one to two seeds. 



Mendoncia coccinea Veil., collected by the writer at Paineiras 

 in the tropical forest on the mountain of the Corcovado near 

 Rio de Janeiro, Brazil, at about 608 meters (2,000 feet) on 

 July 18, 1927, is a woody vine. The velvety, twining stems are 

 provided with opposite, ovate, simple leaves, velvety pubescent 

 on the lower and upper surfaces, 40 mm. broad and 65 mm. long 

 and with short, pubescent petioles, 6-8 mm. long. (Fig. A) 

 The velvety peduncles of the flower arise from the axils of the 

 foliage leaves and are about 30 mm. long surrounded by the 

 opposite bracts, which are about 20 mm. long and 8 mm. wide. 

 This pair of bracts is tightly closed together, like a bivalved 

 clam, or oyster, and thus protect the small red flower bud. 

 (Fig. B.C.) Each bract is papillate inside with numerous low 

 multicellular capitate hairs that conform to the type of secre- 

 tory hairs. (Fig. D.F.) In this case they secrete the water 

 which accumulates in the space between the tightly adherent 

 bracts, (Fig. B) whose margins and external surfaces are covered 

 with straight, or slightly bent, several-celled hairs. (Fig. D.E.) 

 These hairs form an external felt-like covering which prevents 

 the loss of the water of internal secretion, which keeps the 

 flower buds moist and prevents desiccation until the bracts 

 separate and the flower buds are fully blown. The figures ac- 

 companying this short account of an interesting tropical 

 liane display the general morphology of the plant, and the mic- 

 roscopic structure of the hairs which are of importance in pro- 



66 



