100 



swingle: chaetospermum 



Africa, belonging to the hard-shelled citrous fruits, it became 

 necessary to look up all the known plants of this group. This 

 resulted in bringing to light a new species of wood apple from 

 Indo-China, the type of a new genus^ closely related to Feronia. 

 A reexamination of the tabog, undertaken at the same time 

 was facilitated by a fruiting specimen in the National Herbarium 

 collected by E. D. Merrill (No. 3641, Concepci6n, Prov. Tarlac, 



Luzon, November, 1903), and 

 showed that this species differs 

 from Belou marmelos in flower, 

 fruit, leaf and germination char- 

 acters so profoundly that it must 

 be put in another genus. The 

 stamens of the tabog are ten in 

 number, being twice as many 

 as the petals instead of very 

 numerous (more than four times 

 as many as the petals) as in the 

 bael fruit. The ovary of the 

 tabog has 8 to 10 cells instead 

 of 10 to 15 commonly found in 

 the bael fruit. The fruit is ob- 

 long or long oval with low longi- 

 tudinal ridges corresponding in 

 number and position to the seg- 

 ments, and has a thick leathery 

 rind. The bael fruit is spherical or pyriform, never ridged, and 

 has a very hard, woody rind. 



The cells of the tabog fruit are lined with a spongy tissue 

 showing very large cavities or vacuoles. Nothing of the sort is 

 found in any other of the hard-shelled citrous fruits (see fig. 1). 

 The leaves of the tabog are persistent instead of deciduous 

 as in the bael fruit and have smaller, more rounded lateral leaf- 

 lets. On germination the cotyledons become aerial in the tabog 

 but remain hypogeous in the bael fruit. 



Already in 1846 Roemer in his Synopses monographicae made 

 a subgenus, Chaetospermum, under the genus Limonia, for this 



2 This will appear shortly in the Bulletin de la Society botanique de France 



Fig. 1. Cross section of a fruit of 

 Chaetospermum glutinosa (Concep- 

 ci6n, Luzon, November, 1903, E. D. 

 Merrill, No. 3641). Natural size. 

 Shows the thick rind with long slender 

 pointed oil glands; a thin intermedi- 

 ate layer; and an endocarp composed 

 of spongy vesicular tissue (thickened 

 ovary walls) surrounding the cells. 

 The pith is not vesicular. 



