642 



PLANTAGINACEiE. 



[Perigynous Exogexs. 



Fig. CCCCXXIX. 



Order CCXLVI. PLANTAGINACEiE.— Ribworts. 



Plantagines, Juss. Gen. 89. (1789).— Plantagineae, R. Brown Prodr. 423. (1810); Endl. Gen. cxvi.; 

 Meistier, p. 315; Leydolt, die Plantagineen ; Bamioud Recherches sur le Developpement, ^c, des 

 Plantaginees . 



Diagnosis. — Cortusal Exogens, with stamens alternate ivith the petals^ 1 styUy and a straight 



infioresceiKe. 



Hei-baceous plants, usually stemless, occasionally with a stem. Leaves fonning 

 rosettes, or in the caulescent species both alternate and opposite ; flat and ribbed or 

 taper and fleshy. Flowers in spikes, rarely sohtary, usually p , seldom by abortion ^ ? . 



Calyx imbricated in aestivation, 4-parted, persis- 

 tent. Corolla membranous, monopetalous, hypo- 

 gynous, persistent, \\ith a 4-parted limb. Stamens 

 4, inserted into the corolla, alternately with its 

 segments ; filaments filiform, flaccid, doubled in- 

 wards in aestivation ; anthers versatile, 2-celled. 

 Ovary composed of a single carpel, sessile, without 

 a disk, 2-, very seldom 4-celled, the cells caused 

 by the angles of the placenta ; ovules peltate 

 or erect, solitary, t^^in, or indefinite ; style sim- 

 ple, capillary ; stigma hispid, simple, rarely half- 

 bifid. Capsule membranous, dehiscing trans- 

 versely with a loose placenta bearing the seeds on 

 its svu'face. Seeds sessile, peltate, or erect, soh- 

 tary, twin, or indefinite ; testa mucilaginous ; 

 embryo lying across the hilum in the axis of 

 fleshy albumen ; radicle remote from the hilum, 

 inferior, or in some cases centrifugal. 

 This is a group regardmg whose affinities the opinions of Botanists are unsettled. 

 By Jussieu it was considered apetalous, and placed near Amaranths and Chenopods, 

 the calyx being called bracts, and the corolla calyx ; but this is scarcely an admissible 

 explanation of the stinicture. I formerly stationed it near Leadworts, to which it 

 must be regarded as nearly allied ; but I was certainly wTong in associating it with 

 composite plants and their aUies. Don was, I think, the first to suggest that it might 

 be connected with Primworts by means of Glaux, an apetalous genus belonging to that 

 Order. Latterly M. Barneoud, who has particularly studied the subject, has suggested 

 that the supposed corolla is nothing more than a series of abortive stamens analogous 

 to the membranous cup of Gomphrenas and other Amaranths ; and he adopts the 

 opinion of Jussieu that the Orders of Amaranths and Chenopods are those with which 

 Ribworts ought to be associated. In this opinion I cannot concur. There is nothing 

 to distinguish the corolla of Ribworts from the part so called in other plants, except its 

 thinness and want of vascular texture ; all corollas must, in a morphological sense, be 

 regarded as barren stamens ; and, moreover, the embi-yo and seed of Ribworts are 

 totally different from anythmg known in the Chenopodal Alliance. It appears to me 

 that Don's idea was correct, and that upon the whole the Order is a near ally of the 

 Primworts. 



The ovary of Plantago does not present distinctly the appearance of a free central 

 placenta. But in reahty the placenta is at first quite free, although eventually it is 

 pressed close to the sides of the ovary, and thus di\ades the cavity into 2 or more cells. 

 This is, however, only a temporary contact, for long before the seeds are ripe the pla- 

 centa shrinks so much as to lose its adhesion with the sides of the ovary, and then it 

 becomes truly free. In Plantago arborescens it is, when ripe, continuous toith the 

 stigma, and the two become loose and may be removed together, leaving the sides of 

 the ovary undisturbed. 



The tendency to diclinism is very striking in the genus Littorella, and also occurs in 

 Bougueria ; it is not, however, perfect, for the male Littorellas have the rudiment of an 

 ovary. 



The species are scattered over the whole world, in almost every quarter of wliich 



Fig. CCCCXXIX. 

 , section of it. 



-Plantago lanceolata. 1. flower and bract ; 2. pistil ; 3. ovary cut across ; 4. seed ; 



