VERBENACE^ ' 789 



or often a shrub, with numerous low stems. Winter-buds globose, nearly immersed 

 in the bark, and covered with hoary pubescence. Bark of the trunk ye'-^ thick, 

 light brown tinged with red, the surface separating into minute appressed scales. 

 Wood heavy, exceedingly hard, strong, close-grained, clear bright red, with thin 

 lighter colored sap wood. 



Distribution. Cape Canaveral to the southern keys, Florida; common and of 

 its largest size in the United States on the shores of Bay Biscayne near the mouth 

 of the Miami River; northward usually a low shrub; also on the Bahamas and on 

 many of the Antilles. 



2. AVICENNIA, L. 



Trees, with coriaceous persistent leaves, stout pithy branches thickened at the 

 nodes and marked by interpetiolar lines, and long thick horizontal roots producing 

 numerous short vertical thick and fleshy leafless stems rising above the surface of 

 the soil. Flowers opposite, cymose, in centripetal pedunculate spikes or heads, closely 

 invested by a bract and 2 bractlets, the peduncles solitary or in pairs in the axils of 

 upper leaves and ternate on the ends of the branches, their bracts and bractlets con- 

 cave, acute, apiculate, keeled on the back, scarious, slightly ciliate on the margins, 

 shorter than the corolla, persistent under the fruit; calyx cup-shaped, coated like the 

 bracts and bractlets with canescent pubescence, divided nearly to the base into 5 con- 

 cave ovate rounded lobes imbricated in the bud; corolla campanulate, white, with a 

 straight cylindrical tube shorter than the glabrous or tomentose spreading l-lobed 

 limb, the posterior lobe usually larger than the others; stamens exserted; filaments 

 short, filiform, slightly thickened at the base; anthers ovate; ovary ovate, pubes- 

 cent, 1-celled, gradually narrowed into an elongated slender style divided at the 

 apex into 2 lobes stigmatic on their inner face ; ovules 4, suspended from the summit 

 of a free central placenta, orthotropous, naked. Fruit an ovate oblique compressed 

 1-seeded capsule apiculate at the apex; pericarp thin, light green, villose-pubescent 

 on the outer surface, longitudinally veined on the inner surface, opening by the 

 ventral suture and displaying the enlarging embryo before separating from the 

 branch, ultimately 2-valved. Seed naked, without albumen; embryo filling the cavity 

 of the fruit, light green; cotyledons thick and fleshy, broader than long, slightly 

 pointed, deeply cordate at the base, unequal, conduplicate ; radicle elongated, clavate, 

 retrorsely hirsute, inferior, descending obliquely and included between the lobes of 

 the cotyledons slightly attached near the apex in the bottom of the capsule to the 

 withered columella by a minute papillose point; plumule hairy. 



Avicennia with thirty species is widely distributed on maritime shores of the 

 tropics of the two worlds, with one species reaching those of southern Florida. 

 Avicennia produces hard strong wood. The bark is rich in tannic acid, and is used 

 for tanning leather. Its chief value is in the ability of these trees to live on low 

 tidal shores, by the structure of the embryo, which is growing and ready to take root 

 as soon as it falls into the soft mud, and of the long horizontal roots furnished with 

 short vertical fleshy leafless branches or aerating roots and forming a close network 

 which holds the soil together, preventing it from being washed away by outflowing 

 tides and extending the growth of the tree by producing numerous stems soon 

 forming dense thickets. 



The generic name is in honor of the most illustrious physician of the Orient, 

 Avicenna of Bokhara (980-1036). 



