swingle: new genus pleiospermium 427 



Pleiospermium (Engler) Swingle, gen. now 

 Small trees with glabrous branchlets, sometimes with a single stout 

 spine (or two spines) at the side of the bud in the axil of the leaf, some- 

 times spineless, especially the fruiting branches. Leaves typically 

 trifoliolate with the lateral leaflets much smaller than the terminal 

 one, sometimes bifoliolate or unifoliolate (very often so in P. dubium), 

 of medium thickness, glossy above, finely netted-veined beneath; 

 lateral veins slender, not very conspicuous, making a very obtuse 

 angle with the midrib; margin entire, the apex obtuse or subacute, 

 rarely acuminate, bluntly rounded at the very tip, the leaflet blade 

 abruptly narrowed to a cuneate base; petiole variable in length, nar- 

 rowly winged (in P. dubium sometimes nearly apterous), articulated 

 with the blade. Flowers small, about 12 to 15 mm. in diameter, 

 4-5-merous, borne on rather short, finely pubescent pedicels, in clus- 

 ters in the axils of the leaves or in a terminal much-branched hoary 

 panicle. Flower buds cylindric, rounded at the tip, more or less pubes- 

 cent; calyx small, 4-5-lobed; sepals deltoid, finely pubescent. Petals 

 oblong or ovate, obtuse, entire, sparingly covered with fine pubescence 

 on the outer surface. Stamens free, 8 or 10 (twice as many as the 

 petals); filaments free; anthers large, erect, linear-oblong or oblong. 

 Pistil subsessile, seated on a low annular disk; style slender, gradually 

 merging with the tip of the ovary, ending in the somewhat thicker 

 capitate stigma; ovary ovate, 4- or 5-celled, with 2 ovules in each 

 cell. Fruits globose, like a small orange in appearance, the cells con- 

 taining one or two seeds surrounded with an aromatic, mucilaginous 

 fluid, and, at least in P. dubia, having short, slender pulp vesicles 

 scattered on the inner ovary wall. Peel rough, dotted with numerous 

 oil glands. Seeds oval, flattened; germination unknown. 



Type species, P. alatum {Limonia alata Wight & Arm), native to 

 southern India and Cejdon. 



Geographic range: India, Ceylon, Java, and adjacent islands (?). 



The genus Pleiospermium is most closely related to Pamburus and 

 Merope, having soft-rinded fruits resembling very small oranges or 

 lemons in appearance but having only 4 or 5 cells, filled with a glutinous 

 fluid, each cell containing 1 or 2 seeds. All three of these genera are 



laminis articulatis; laminae tenues superne nitidae subtus reticulatae. Spinae 

 rectae axillares solitariae vel binae vel carentes. Inflorescentiae pubescentes, 

 5-15-florae; flores mediocres, 4- vel 5-merae ; petala alba oblonga; stamina libera, 

 8 vel 10, filamentis tenuibus; stylus tenuis, ovario paulo longior; stigma capita- 

 turn diametro stylo paulo majus; ovarium 4-5-loculare, ovulis in loculo binis. 

 Fructus parvus, subglobosus, cortice ut in Citro carnosa, parietibus ovarii vesi- 

 culis brevibus instructis, loculis 1-2-spermis, liquore glutinoso aromatico re- 

 pletis. Semina complanata, ovalia. 



Arbusculae ramosae spinosae vel inermes, ramulis junioribus tenuibus plus 

 minusve angulosis. Species typica, Pleiospermium alatum {Limonia alata Wight 

 & Arn.). Habitat in India, Zeylona, et Java. 



