158 



NATURAL HISTORY OF PLANTS. 



Pseudosciadium 

 Balansce. 



in enormous clusters of umbels. The petals are valvate, attenuate at 

 the base and constructed Hke those of an Umbillifer, with an internal 

 middle crest dividing them into two cavities each of which receives an 

 anther cell. The flowers are borne on a pedicel with an articulation 

 distant from the base of the ovary and are dimor- 

 phous as regards stylary branches. The latter 

 are either very short, rectilinear (in flowers pro- 

 bably sterile), or long, thick above and stigmati- 

 ferous at the summit and along the margins of 

 an internal longitudinal furrow. The two-celled 

 ovary and the young fruit are compressed perpen- 

 dicular to the partition ; but at this age no trace 

 of aliform dilatation is seen. The leaves are 

 compound-imparipinnate. 



Machinlaya macrosciadea, a tree from tropical 

 eastern Australia, is also one of the types which 

 connect the AraUece with the Umbelliferce proper. 

 A distinct tribe has been made of it because it 

 has, like the two preceding genera, petals attenuate 

 at the base, concave, divided internally by a middle 

 crest. The acuminate summit is still more 

 manifestly induplicate. They are, in fact, true 

 petals of Umhelliferce ; the prefloration is valvate 

 like that of Pseudosciadium. The inflorescences 

 are decompound umbels ; the ovaries two-celled ; the fruit is a drupe 

 of little thickness, but hard, didymous and much compressed perpen- 

 dicular to the partition, and the leaves are digitate, with membranous 

 stipules adnate to the base of the petiole. The floral pedicels are 

 said to be articulate. 



Having analogous petals with constricted base, ciliate margins and 

 pointed summit, Ainopetalum (fig. 197-199), stubby shrubs of New 

 Caledonia, present a habit and foliage quite exceptional in this 

 group. Near the ends of the branches they have alternate simple, 

 oval or oblong, dentate, penninerved, glabrous or hairy leaves, 

 with umbels united in compound pedunculate corymbs, and floral 

 pedicels without articulation. The ovary, in great part inferior and 

 imbedded in the obconical concave receptacle, is 2-4-celled, and 

 the style divides above into the same number of obtuse lobes. The 



Fig. 196. Fertile 



flower without petals 



and stamens (f). 



