EUPHORBIALES.] 



EUPHORBIACE^. 



'Z(0 



most agree, and especially with the former. Their habit, indeed, and general appear- 

 ance, are in certain instances so much alilve that one might easily mistake some Crotons 

 Aleurites, «&c., for ^Mallowworts ; the starry structm-e of their hairs, their monadelphous 

 stamens, the definite number of ovules in a definite number of united carpels, are all 

 further points of resemblance. As to the relationship of Spurgeworts to Rhamnads it 

 was long ago perceived by Jussieu, and has been smce adverted to by Adolphe Bron"-- 

 niart (Monogr. des Rhamn. p. 35.). Browai, too, in omitting Spurgeworts from the 

 apetalous Orders, in his Prodromus, may be conjectured to have entertained a similar 

 opinion; and Auguste de St. Hilau'e inquires whether they are not intermediate between 

 Mallowworts and Menispermads. A writer in the Linncea (14. 2.50.), would place this 

 Order next Byttneriads, and it is no doubt to that form of the Malval Alliance that it 

 approaches nearest. 



But if, v\'ith Jussieu, we consider the separation of sexes a great physiological charac- 

 ter, the Order of Spurges will join that of Nettles, through Eremocarpus, a curious 

 Californian plant lately discovered by Mr. Bentham, which indeed might be refeiTed 

 inchfferently to Spurgeworts or Artocarpads. And so again with Antidesmads, their 

 character is very Httle different from that of such drupaceous Spurgeworts as Sarcococca. 

 Nor can their close connection ^vith the Garryal AUiance be overlooked ; for Helwinwiads 

 are scarcely more than Spurgeworts with an adherent ovary and minute embryo. 



Misled by imperfect information, I formerly proposed a gi'oup called Trewiaceae ; 

 but it has been shown by Klotzsch, who has had the opportunity of examining authentic 

 materials concerning Tre^\ia, that it is really a tetracoccous genus of the present Order, 

 nearly allied to Rottlera, {Wiegm. vii. 257). Although there does not appear to be any 

 considerable affinity between this tribe and Cucurbits, yet it is to be noted that several 

 genera have a scrambling habit, that the number 3 prevails in the ovary of both Orders, 

 and that the genus Peripterygium has, according to Hasskarl, the habit of a Momordica. 

 There seems to be notliing in Putranjiva to distinguish it from a drupaceous Spurgewort. 



In general the structm-e of Spm-geworts is very uniform, and upon the whole there 

 are few extensive Orders in which it is less liable to exceptions. Some, however, of a 

 very striking kuid do occur. Foremost among the 

 instances of anomalous stinictui'e is the common Spurge, 

 (Euphorbia), in which the involucre is so much hke a 

 calyx, and sometimes seems to be even augmented with 

 petals, that a student finds it difficult to believe that it is 

 7 



Fig. CLXXXVIII. 



Fig. CXC. 



reaUy composed of numerous naked $ flowers surroundmg a ? equally destitute of 

 calyx and corolla. The real history of the structure is however proved m many ways, 

 and especiaUy by such plants as Monotaxis, in which there is also a number ot S flowers 

 surrounding one ? , but each is furnished with a calyx, and the cup-like mvolucre which 

 disguises Euphorbia is reduced to a few scales. Besides these instances ot anomalous, 

 structure, we find the carpels reduced to 2 in Mercurialis, &c., or even 1 in Eremocarpus 



The 



and Peripterygium, or mcreased to as many as 9 m Anis onema, or 15 m Hura. 



Fig. CLXXXA'III.--l.TheinvolucreofaEuphorbia,containingmonandrous male fl^^^^^^^^ 

 a long-stalked female ; 2, 3, 4. male florets of different species, with the articulation tMt separates the 

 filamlnt from the pedicel; 5. a carpel separate ; 6. a vertical section of an ovarj ; 7. a vertical section 

 a ripe seed, showing the central column and an embryo in the midst of albumen. 



Fig. CLXXXIX.— The involucre of Euphorbia Lathyrir,. . 



Fig. CXC— Perpendicular section of the seed of Euphorbia Lathyiis. 



T 2 



