WAHOO 409 



CELASTRACEJE, OR STAFF-TREE FAMILY 



The plants are trees, shrubs or woody climbers, represented 

 by about 350 species, which are widely distributed. The leaves 

 are simple, the flowers are small and regular, the fruit is a some- 

 what fleshy dehiscent pod, and the seeds usually have a reddish 

 or purplish aril. The plants: are furthermore distinguished by the 

 development of caoutchouc-containing elements in the phloem. 

 These resemble laticiferous tubes, having narrow lumina and caout- 

 chouc-like contents, which are soluble in chloroform, ether and sim- 

 ilar solvents. They are frequently so abundant, as in Euonymus, 

 that on breaking the bark, the fragments remain connected by the 

 tough elastic threads. The bast fibers in this family are usually 

 associated with crystal fibers and the sieve tubes frequently possess 

 scalariform sieve-plates. The tracheae show a tendency to develop 

 scalariform perforations. Calcium oxalate is secreted in the form of 

 solitary crystals or rosette aggregates. The cork-wings, which are 

 peculiar to a number of species of Euonymus, are due to the devel- 

 opment of cork in the parenchyma of the cortex. This usually arises 

 at 4 different points, thus elevating the epidermis and giving the 

 branches a 4-angled or slightly winged character. 



EUONYMUS. Wahoo Bark. The dried bark of the root of 

 Euonymus atropurpureus (Fam. Celastracese), a shrub (Fig. 175) 

 indigenous to the central and eastern United States and Labrador. 



Description. Usually in transversely curved pieces, occasionally 

 in single quills, 3 to 7 cm. in length, 0.5 to 1.5 cm. in diameter, bark 

 0.5 to 1 mm. in thickness; very light; outer surface light brown, 

 somewhat wrinkled, with scaly patches of soft cork, few lenticels, 

 root-scars and adhering roots, which frequently perforate the bark; 

 inner surface light brown, longitudinally striate, somewhat porous, 

 occasionally with small pieces of yellow wood adhering; fracture 

 short, with silky, projecting, caoutchouc fibers, cork light brown, 

 inner and middle bark somewhat tangentially striate and with irreg- 

 ular, dark-brown bast areas ; odor faint; taste bitter; acrid (Fig. 175). 



The stem bark occurs in very long, fibrous strips with a grayish- 

 black cork and should be rejected. 



Inner Structure. (Compare with. Fig. 175). Periderm of 

 numerous tangentially elongated, thin-walled cork cells;.- the outer 

 layers being grayish-brown and somewhat compressed; the inner 

 layers of somewhat rectangular, slightly lignified cells; primary 

 cortex of isodiametric starch-bearing parenchyma, among which 

 are distributed the laticiferous tubes having narrow lumina and a 



