66 NATURAL HISTORY OF PLANTS. 



apex. Calyx toothed or lobed, more rarely polysepalous and short 

 or nearly absent or composed of minnte cilia. Petals free or 

 oftener both connate and adnate to stamens to a variable height, 

 valvate in aestivation. Stamens go, usually very numerous; fila- 

 ments slender exserted, hypogynous or oftener somewhat perigynous, 

 inserted at summit of receptacle or under disk either free, or mona- 

 delphous {Lophanta) or polyadelphous just at base or rarely to a 

 greater height {Albizzia), or monadelphous forming a long exserted 

 tube {Zygid), always free at apex ; anthers small introrse 2 -celled 

 2-rimose; pollen-grains usually aggregated in 2-4- masses in each 

 cell. Germen sessile or stipitate, 2- co-ovulate ; ovules 2-seriate 

 descending ; micropyle extrorse superior ; style slender ; apex trun- 

 cate or minutely capitate, stigmatiferous. Legume ovate, oblong 

 or linear, plane convex or terete, straight or bowed, more rarely 

 variously twisted, membranous coriaceous or ligneous, 2-valved or 

 indehiscent, continuous, stuffed or septate within, more rarely sepa- 

 rating transversely into 1 -seeded segments. Seeds transverse or 

 descending, ovate or suborbicular, compressed ; funicle short straight 

 or longer pendulous, more rarely very long corrugated or folded, 

 variably dilated into a fleshy aril. — Trees or shrubs, very rarely herbs, 

 unarmed prickly or spiny ; leaves alternate 2-pinnate ; leaflets 

 usually minute cc -jugate, more rarely reduced to a compressed leaf- 

 like petiole or phyllode ; petiolar gland often more or less conspi- 

 cuous ; stipules 0, or of variable form, minute, more rarely broader 

 membranous, sometimes spinescent straight or curved ; flowers 

 small, usually crowded, in globose heads or cylindrical dense or 

 interrupted pedunculate spikes ; peduncles axillary, solitary or gemi- 

 nate or more rarely fascicled or else in racemes at extremities of 

 branches {Tropical Australia and Africa, all hot regions). See p. 37. 



21. Xnga Plum. — Flowers 5-, more rarely 6-merous (of Acacia), 

 hermaphrodite or more rarely polygamous ; stamens connate at 

 base to a variable height, forming a tube, usually at the same time 

 adnate to base of corolla. Ovary sessile cc -ovulate ; style subulate ; 

 apex truncate or capitate, stigmatiferous. Legume linear, straight 

 or slightly curved, plane 4-gonous or terete, coriaceous or subcarnose, 

 scarcely dehiscent ; sutures usually dilated thick furrowed. Seeds 

 bare or enveloped in a sweet pulp. — Trees or shrubs, unarmed; 

 leaves abruptly pinnate ; leaflets often large ; petiole generally winged 



