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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 10 



2, rarely 3, winged, flattened, broadly ovate, rounded at the base, and attenuated 

 at the tip into a bifid apiculum. Seeds lack endosperm and have a straight 

 embryo. Harms (1931b) added that he did not observe any resin canals, that 

 the bark and leaves were weakly bitter, and that tufted hairs occurred on the 

 edges of sepals and petals. Steyermark's (1952) description of D. fruticosa, 

 based on non-flowering material, is essentially the same as that for the genus as 

 given by Harms (1931a), but he mentioned the occurrence of punctae in the 

 leaves. The geographic distribution of Diamma appears to be restricted to the 

 Roraima sediments of the Guayana region of north-central South America. 



Ule (1914), in describing the vegetation of Roraima, mentioned "... eihe 

 merkwiirdige neue Gattung der Simarubaceen, Diomma TJlei Engl." Harms 

 (1931a), in validating Engler's description of this species, remarked that the 

 position of Diomma is uncertain. He stated that the apotropous ovules differ 

 from those of genuine Simaroubaceae and from those of the Geraniales as a 

 whole. However, he placed it under Simaroubaceae because Engler had consid- 

 ered it under that family. Nevertheless, later in 1931, Harms delved further 

 into the relationships of Diomma and averred that the apotropous ovules sug- 

 gested an alliance with Sapindales, but that a close relation in this order would 

 be difficult to find. Diomma was placed in the simaroubaceous tribe Picram- 

 noideae next to Alvaradoa by Cronquist (1945). Steyermark (1952) mentioned 

 that, "The large leaf-scars and long-pinnate leaves of this genus resemble some 

 genera, such as AUanthus, of the Simarubaceae . . . but the punctate leaves of 

 D. fruticosa may show a closer affinity or connection with Rutaceae, to which 

 family it is here assigned." 



Sohnreyia. 



The genus Sohnreyia is represented by a single species, S. excelsa, which was 

 described by Krause (1914) from specimens gathered by Ule. Sohnreyia- like 

 Diomma, is one of those dicotyledons with a palm-like habit. Krause describes 

 this plant as an erect, palm-like tree with a slender unbranched trunk bearing 

 very large pinnate leaves crowded at the apex. Also, like Diomma, Sohnreyia 

 is a species which blooms and fruits but once at the termination of its existence 

 (Krause 1921; Ducke 1930). 



Krause (1914) notes that the large, pinnately compound leaves of Sohnreyia 

 are glandular-punctate. Flowers are white, regular, polygamous, 5-merous, and 

 disposed in loose, many-flowered panicles. The free stamens are inserted at the 

 base of a gynophore opposite the sepals. In the female and bisexual flowers, 

 stamens are smaller than in the male flowers. The filaments are provided with 

 a wing-like, bifid appendage in the lower part. The 2-locular ovary is inserted 

 on a thick, subcylindrical gynophore. Ovaries are small, rudimentary, and 

 estigmatose in male flowers, but in female and bisexual flowers the ovaries are 

 larger, somewhat laterally compressed, and in females bear a short style termi- 

 nated by a fairly large, bilobed, discoid stigma. Ovules are pendulous, ana- 

 tropous, and solitary in each locule of the ovary. Krause did not see fully 

 developed fruits. However, in 1922, Ducke described the fruits of Sohnreyia 

 as resembling the samaras of certain Combretaceae, e.g., Terminalia argentea. 

 However, he noted that the fruits of Sohnreyia were 2-seeded, dry, and with 2 

 membranous confluent wings which are conspicuously reticulate. According to 

 Ducke and Black (1953), Sohnreyia excelsa is scattered in Brazil on uplands 



