PAP AVERAGES. 131 



one-celled ovary and parietal placentation whose affinities with the 

 Polycarpicce are not yet clearly settled, certain genera that recall 

 Papaveracece by their sexual organs ; such as Parnassia and several 

 Cistacece, Bixacece, 1 and Capparidacete. 



The vegetative organs of Papaveracea are to some extent charac- 

 teristic. We may note the usually herbaceous stems, often glabrous 

 and glaucous, or covered with long hairs, which may be harsh and 

 prickly. Only in two, Bocconia and Dendromecon, does the frutescent 

 stem become woody, at least in its lower part. A far more marked 

 character of organization is the presence of a white or coloured milky 

 juice in most Papaveracea. In some it becomes opalescent and trans- 

 lucent, and in Fumariea almost exclusively the juice is quite or nearly 

 transparent in stem and leaves. The Papaveracecs have always been 

 cited as typically rich in proper juice or latex. 



The laticiferous vessels of Papaveracece, formerly imperfectly 

 described, 2 have been recently studied by Tkecul. 3 He finds 

 two types of structure and distribution of these vessels in 

 Papaveracea. " In the one type they are chiefly allotted to the 

 circumference of the fibrovascular bundles of the aerial stems and 

 leaves {Chelidonium, Macleya, Sanguinaria, &c). In the other they 

 are only present in the subliberian tissue of the fibrovascular bundles 

 of these same organs ; hence in neither case is it the liber fibres alone 

 that contain the latex ; which, however, does not imply that the 

 laticifers have none of the characters of these fibres. The Papa- 

 veracece .... on the contrary, will serve to show that these vessels 

 are formed of elements that vary with the parts they traverse — i.e., 

 in the parenchyma they are formed from cells like those of the 

 parenchyma ; in contact with the liber they may be formed of cells 

 like those of the liber, and susceptible of similar thickening, &c." 

 In Papaver, Argemone, and Ba j meria the laticifers are seen in the sub- 



1 Especially Cocldospermece, made a tribe of the laticiferous cells. (See also Amici, in Ann. 

 tbis order, but sometimes possessing the habit of Sc. Wat., ser. 1, i. 224, t. 13. — Link, Icon. Anat., 

 Papaveracea. Cochlospermum has, it is true, fasc. 2, xiv. 8. — C. H. Schttltz, in Nov. Act. 

 pentamerous flowers, but the structure of its Nat. Cur., xviii. Suppl. ii. t. 16, 17.) 

 gynseceum recalls that of a Poppy, and its latex 3 In Compt. Bend., lx. 522; in Adansonia, 

 is yellow, as in Boemeria, Argemone, &c. vii. 145 ; in Ann. Sc. Nat., ser. 5, v. 44. — This 



2 By Moldenhatter, who in 1812 (Beitr. z. work it is that we summarize here, and to it we 

 Anat. d. Pfianz., 141), described those of Cheli- refer the reader for the numerous details of the 

 ionium, and since by Unger, Hanstein, &c, question. 



who have recognised the arrangement in rows of 



K 2 



