24 NATURAL HISTORY OF PLANTS. 



more flattened out than in the preceding genera, and is lined by a 

 thick disk whose rim presents ten projections, alternating with 

 which are as many notches corresponding with the stamens. These 

 last are more external, and their filaments, exserted in anthesis, are 

 twisted or corrugated in the bud. The gynseceum is borne on a 

 slender stalk, and the style ends in a slight stigmatic dilatation. 

 The pod is compressed and thick-walled, the endocarp projecting 

 between the seeds to form more or less complete partitions. The 

 pericarp finally opens down both edges. The seeds are attached to 

 its interior by elongated funicles more or less bent on themselves. 

 Stn/phnodendron consists of trees or shrubs from tropical America. 

 Their leaves are bipinnate, whose usually sessile leaflets, nearly as 

 broad as long, have hairs scattered irregularly over their surface. Their 

 flowers are also sometimes polygamous ; they grow in axillary racemes 

 like those of Adenanthcra. About half a dozen species are known. 1 



The flowers of Piptadeiiia' resemble those of Sfr//jj////odrj/dron, 3 

 and are sessile or shortly pedicellate. 4 They are hermaphrodite or 

 polygamous, arranged either in more or less elongated racemes, or 

 in spikes, which again may be also elongated, or else very short and 

 sometimes globular (capitula). These inflorescences are pedunculate, 

 axillary or terminal, either simple and solitary, or ramified. The 

 pod, sessile or more frequently stipitate, opens like that of Stryphno- 

 dendron, by two longitudinal clefts ; but it has only a single cavity 

 containing seeds suspended by slender funicles, for its membranous 

 or coriaceous walls present no thickenings or false dissepiments 

 between the seeds. In Piptadenia proper' the pericarp is thin and 

 smooth or reticulate. In Pytirocarpa 6 the valves, thicker and more 

 or less wrinkled on the surface, have their edges more or less pushed 

 inwards in the intervals between the seeds. In both of these sub- 

 genera the flowers are racemose. But Niopa, with the fruit of 

 Pytirocarpa, has a capitular inflorescence ; while in a fourth small 

 group, which we may term Piptoniqpa, the fruit is that of Piptadenia 



1 Attbl., Ghiiait., ii. 938, t. 357. — Velloz., rugated in the bud, but are afterwards long and 

 Fl. Flwm., xi. t. 7. — Pcepp. & Ende., Nov. exserted in tbe flower, the ovary is stipitate, 

 Gen. et Spec., m. t. 291. — Walp., Sep., i. 860 ; often hairy, and is surmounted by a truncate 

 v. 579. style ; the ovules are descending, with the mi- 



2 Benth., in Hook. Journ., iv. 334. — B. H., cropyles looking upwards and outwards. 

 Gen., 589, n. 376. * The pedicels are articulated at either end. 



3 These flowers are normally pentamerous, 5 Fupiptadenia B. H., Gen., 590. 

 the receptacle is small and cupuliform with 6 B. H., Gen., loc. cit. 

 rounded fleshy edges ; the stamens are first cor- 



