54 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN- [VOL. 10 



unappendaged filaments as in Diomma ulei are found in S. glabrescens Planch. 

 {Steam 1003). Illustrations of these examples occur in figure 2. 



Locules in Spathelia as in Diomma are uniovulate. Although Bentham and 

 Hooker (1862) and Engler (1931) mention geminate ovules in the locules of 

 Spathelia, Fawcett and Rendle (1920) state: . . ovules one in each cell . . . 

 pendulous from the inner angle at the apex of each ovary-cell." The authors 

 have also observed only uniovulate locules in ovaries of female flowers of 8. 

 simplex and 8. mbintegra. Furthermore, it can be demonstrated that the ovules 

 in Spathelia are apotropous as in Diomma. It is worthy of note in this regard, 

 that even in 1858, Agardh presumed that ovules of Spathelia were apotropous 

 from Gaertner's description of the seeds of S. simplex (1788). Dorsal, elongate 

 secretory cavities occur in the carpels of Spathelia (fig. ID) as in those of 

 Diomma. However, they are more conspicuous in Spathelia, especially in the 

 fruiting condition. 



Differences, of course, do occur between Spathelia and Diomrna. The leaves 

 in Spathelia may be many-foliolate — up to 100-jugate; whereas in Diomma, 22 

 pairs of leaflets appear at present to be maximal. Leaflets in Spathelia are 

 generally small to medium-sized (up to 15 cm long in 8. glabrescens and to 20 

 cm long in S. simplex), and only rarely entire. In Diomma, on the other hand, 

 leaflets are generally large and entire. 



Aestivation of sepals in Spathelia follows two patterns: valvate (e.g. S. 

 glabrescens and S. subintegra) and imbricate (S. cubensis and S. simplex). In 

 Diomma. sepalar aestivation is imbricate. Although glandular cavities occur at 

 the tips of perianth parts in Diomma, they are tiny and inconspicuous compared 

 with those of Spathelia. 



The ovary in Spathelia is regularly 3-carpellate and 3-locular*^.nd only rarely 

 2-carpellate and 2-locular (Fawcett & Rendle 1920). On the other hand, the 

 ovary in Diomma is generally 2-carpellate and 2-locular. 3-carpellate and 3- 

 locular ovaries being of exceptional occurrence (fig. 1). The fruits of Spathelia 

 are narrowly winged; those of Diomma possess broad wings. Seeds of Spathelia 

 contain a fleshy endosperm, whereas Diomma seeds are lacking in endosperm. 

 The embryo in Spathelia has linear-oblong cotyledons, but these are suborbicular 

 to ovate in Diomma. 



The Position of Diomma in Rutaceae. 



From the foregoing discussion it is not too presumptuous to state that Diom- 

 ma has a definite and more or less close relationship to Sohnreyia and Spathelia. 

 Sohnreyia excels a is the only member of the subtribe Sohnreyiinae of the tribe 

 Toddalieae, subfamily Toddalioideae. It might seem reasonable to place Diomma 

 in this subtribe with Sohnreyia, and to raise Sohnreyiinae to the rank of sub- 

 Family, because of the presence of apotropous ovules in both genera. However, 

 the subfamily Spathelioideae, of which Spathelia is the sole member, already 

 exists in Rutaceae, and it is .characterized and distinguished .from all other 

 Rutaceae by the presence of apotropous ovules. Therefore, aside from two differ- 

 ences among Diomma, Sohnreyia, and Spathelia to be discussed below, the au- 

 thors can see no reason for not including these three genera in Spathelioideae 

 sensu novo. The only objections which might be raised to the above proposal 

 involve the valvate or "subvalvate" aestivation of sepals, and the endospermous 

 seeds of Spathelia. Sepalar aestivation is imbricate in Diomma and Sohnreyia, 

 and the seeds of these genera lack endosperm. 



