98 



Geography. Natives of Barbary, the Levant, and North America. 



Properties. Noble timber-trees, the wood of which is extremely valuable ; 

 the bark of Platanus is remarkable for falling off in hard irregular patches — a 

 circumstance which arises from the rigidity of its tissue, on account of which it 

 is incapable of stretching as the wood beneath it increases in diameter. 



Example. Platanus. 



LXXXVI. MYRICEiE. The Gale Tribe. 



Mybiceje, Rich. Anal, du Ft. (1808) ; Ach, Rich. Elem. de la Bot. ed. 4. 561. (1828); Lindl. 

 Synops. 242. (1829).— Casuaeineje, Mirbel in Ann, Mus. 16. 451. (1810); R. Brown in 

 Flinders, 2. 571. (1814.) 



Diagnosis. Achlamydeous dicotyledons, with a 1 -celled ovarium, erect 

 ovules, a naked embryo, and amentaceous flowers. 

 Anomalies. Casuarina is leafless. 



Essential Chakacteh. — Flowers diclinous, amentaceous. Stamens 1 or several, each with 

 a hypogynous scale. Anthers 2- or 4-celled, opening- lengthwise. Ovarium 1-celled, sur- 

 rounded by several hypogynous scales ; ovulum solitary, erect, with a foramen in its apex ; 

 stigmas 2, subulate. Fruit drupaceous, often covered with waxy secretions, formed of the hy- 

 pogynous scales of the ovarium, become fleshy and adherent ; or dry and dehiscent, with the 

 scales distinct. Seed solitary, erect; embryo without albumen; cotyledons 2, plano-convex; 

 radicle short, superior. — Leafy shrubs, with resinous glands and dots, the leaves alternate, sim- 

 ple with or without stipula? ; or leafless shrubs or trees, with filiform branches bearing 

 membranous toothed sheaths at the articulations. 



Affinities. The nearest approach made by these plants is probably to 

 Ulmacea? and Betulinere, from the former of which they are readily known by 

 their amentaceous flowers and want of a perianthium ; from the latter they are 

 distinguished by their erect ovula, aromatic leaves, and 1-celled ovarium. In 

 the latter respect they resemble Piperacea 3 , from which, however, they differ 

 materially in other points. The only anomalous genus is Casuarina, which 

 has the habit of a gigantic Equisetum, and which can scarcely be compared 

 with any other dicotyledonous tree. Mr. Brown, in the Appendix to Flinders' 

 Voyage, has the following observations on the structure of this remarkable 

 genus, from which it will be seen that he does not consider it achlamydeous, as 

 I do. 



"In the staminiferous flowers of all the species of Casuarina, I find an envelope 

 of four valves, as Lalillardiere has already observed in one species, which he 

 has therefore named C. quadrivalvis. Plant. Nov. Holl. 2. p. 67. t. 218. But 

 as the two lateral valves of this envelope cover the others in the unexpanded 

 state, and appear to belong to a distinct series, I am inclined to consider them 

 as bractese. On this supposition, which, however, I do not advance with much 

 confidence, the perianthium would consist merely of the anterior and posterior 

 valves ; and these, firmly cohering at their apices, are carried up by the anthera, 

 as soon as the filament begins to be produced, while the lateral valves or brae- 

 tea^ are persistent ; it follows from it, also, that there is no visible perianthium 

 in the pistilliferous flowers ; and the remarkable economy of its lateral bractese 

 may, perhaps, be considered as not only affording an additional argument in 

 support of the view now taken of the nature of the parts, but also as in some 

 degree again approximating Casuarina to Conifers, with which it was formerly 

 associated. The outer coat of the seed or caryopsis of Casuarina consists of a 

 very fine membrane, of which the terminal wing is entirely composed ; between 



