530 DICOTYLEDONES. 



(of whose anthers one half is inserted lower than the other, or suppressed) and the 

 gynoeceum, the Acanthaceas are true Personatae, approaching most nearly to the 

 Scrophulariaceae : they differ from the other orders especially in the fruit, 

 which is a bilocular, 2-valved, often elastically dehiscing capsule, which never 

 has more than 2 rows, and in some only 2 seeds in each loculus, the seeds 

 heing often compressed and borne on strony, curved or hook-like fnnicles (reti- 

 nacula) which persist after dehiscence. Embryo curved without endosperm; 

 radicle pointed downwards. Cleistogamic flowers are found in several species. 

 Cystoliths are common. 



The following grow wild in Europe : Acanthus (spinosus and mollis, whose 

 pinnatitid leaves served as models for the capitals of the Corinthian columns). 

 The posterior sepal is the largest of all the leaves of the flower, and covers the- 

 other parts like a helmet ; the 2 anterior sepals are united, and the two lateral' 

 ones are small and greenish ; the corolla has no upper-lip, but only a 3-lobed 

 under-lip. The anthers are bilocular ; the filaments ultimately become very 

 firm. Justicia, Eranthemum, Goldfussia, Thunbergia (a twiner), ^Ruellia, Die- 

 liptera, etc. Ornamental plants in conservatories. 



Order 9. Plantaginaceae (Plantains). The flowers (Figs. 

 570, 571) are regular, ^, hypogynous, with a 4-part,ite, persistent 

 calyx, a gamopetalous, scarious corolla with 4 projecting lobes,. 

 4 stamens, incurved in the bud, later on projecting considerably, 

 about equal in length, and a bilocular ovary with one long, fila- 

 mentous, undivided, feathery, papillose style (see Fig. 571). The 

 ovary is most frequently bilocular with 1-few ovules in each 

 loculus. An hypogynous disc is wanting. The fruit is a pyxidium 

 with 1-few peltate seeds attached in each loculus (Littorella is in 

 several respects an exception). All species are herbs, the majority 

 with leaf-rosettes near the ground, and the flowers in spikes or 

 capitula. 



The labiate-like flowers are in this case entirely concealed under a regular,, 

 apparently 4-merous exterior. The structure of the flower, however, is the same- 

 as in the Scrophulariacece, only the reduction, which is found in Veronica (com- 

 pare Figs. 562 C, 567 with 570, 571), is also present in this instance and the- 

 lobes are also more equally developed ; the posterior petal corresponds to the bi- 

 lobed upper-lip ; the posterior stamen and the posterior sepal also are entirely 

 wanting. In the development of the flower there is no trace of posterior sepal 

 or stamen, and the posterior petal arises from one primordium, but the two 

 anterior sepals arise before the lateral ones. The position of sepals and petals 

 does not agree with that of a true 4-merous flower, which is represented in Fig. 

 361 E. The bracteoles are always suppressed in Plantago. 



Plantago (Plantain, Rib-grass). The foliage-leaves are most 

 frequently scattered, entire, with curved veins, arranged in a 

 rosette close to the ground on an unlimited rhizome ; the spike- 

 like inflorescence is borne on a long scape ;. in some (P. psyllium)> 



