352 SYSTEMATIC BOTANY. 



LOEANTHACE^. THE MISTLETOE ORDEE. 

 Coh. Santalales, JBenth. et Hook. 



Diagnosis. Shrubby plants with leathery greenish ' foliage, parasitic 

 (naturally grafted) on trees ; leaves opposite, exstipulate ; flowers perfect 

 or diclinous ; perianth adherent, with 4-8 lobes ; stamens 4-8, superposed 

 to the segments of the perianth ; ovary inferior, 1-celled, with 3 ovules 

 pendulous from a free central placenta, or 1, erect, arising from the base 

 of the cell ; fruit succulent ; seed 1 ; embryo in fleshy perisperm ; radicle 

 remote from the hilum. Illustrative Genera : Viscum, Tournef. ; Loran- 

 thus, L. ; Myzodendrori) Sol. 



Affinities, &c. These remarkable plants are distinguished by their 

 peculiar parasitic habit. They are nearly allied to Santalaceee, present- 

 ing, like that Order, a naked nucleus as the representative of the ovule, 

 and are further characterized by the strange extrusion of the apex of the 

 embryo-sac before or after fertilization. Besides the curious structure of 

 the flowers, they have an anomalous organization of the wood, which has 

 no medullary sheath of spiral vessels, but contains scalariform tubes. The 

 germination of the seeds exhibits some interesting phenomena : in Viscum 

 the seeds adhere to the young shoots of trees by means of the viscid pulp 

 of the fruit ; in Myzodendron there are long feathered processes, which 

 coil round the branches on which they settle j in either case the seeds are 

 retained in contact with the surface of the shoot upon which they rest, 

 where they germinate, and push their radicle through the bark down to 

 the cambium-layer, with wnich they contract an organic adhesion and 

 become grafted, just as a bud does in the ordinary gardening operation of 

 budding Roses, &c. According to Van Tieghem the stamen and the sepal, 

 and the carpel and the ovule each correspond to a single leaf, the one 

 organ being a deduplication from the other. The male flower consists of 

 four leaves in decussate pairs, each polleniferous upon the upper face. 

 In the female flower the ovule is reduced to an embryo-sac, which is a 

 cell of the parenchyma of the base of the third pair of bracts or carpels. 

 The embryo of Viscum does not appeal for several weeks after the appli- 

 cation of the pollen. Two or more embryos occur sometimes in one seed 

 and become united together. In Lorantlms no trace even of ovule is ob- 

 servable till after fecundation. Nuytsia has four cotyledons, or perhaps 

 two deeply divided. 



Distribution. A large Order, of which some are European, as Viscum 

 album and Loranthus europceus ; the majority belong to the hotter parts 

 of Asia and America ; Myzodendron belongs to the temperate parts of the 

 southern hemisphere. 



Qualities and Uses. Some of the plants have astringent properties ; but 

 the most important product perhaps is the viscid pulp of the fruit of 

 Viscum album, which is used for making bird-lime. The curiosity attach- 

 ing to the parasitic habit is the most striking feature in this Order, most 

 of the plants growing like our common Mistletoe, Viscum album] this 

 appears capable of grafting itself on a wide variety of trees, being most 

 common on the Apple-tree with us, but occurring on Thorns, Willows, 

 Limes, Oaks, Elms, and even on Fir-trees. 



