640 



PLUMBAGINACEiE. 



[Peiugynous Exogens. 



Order CCXLV. PLUMBAGINACE^.— Leadworts. 



Plurnbagines, Juu. Gen. 92. (1789).-Plumbaginote, R. Brown, Profr. 425. (1810) ; M *£"«2f 

 (,,„: Prod/-. ; J&kH. fen. cxvii.; Maimer Gen. p. 315 ; Barnioud Mimoire, sur let Plumbaginee*. 



Diagnosis.— Cortusai Exogens, with the stamens opposite the petals, membranous one- 

 seeded fruit, 5 styles, and a herbaceous stem. 



Herbaceous plants or under-shrubs, variable in appearance. Leaves alternate or 

 clustered, undivided, somewhat sheathing at the base, but without stipules, sometimes 



marked with transparent dots. Flowers either 

 loosely panicled, or contracted into heads, flower- 

 ing irregularly. Calyx tubular, plaited, persistent, 

 sometimes coloured. Corolla of very thin tex- 

 ture, monopetalous, with a narrow angular tube, 

 or of 5 petals, which have a long narrow claw. 

 Stamens definite, opposite the petals, iu the mono- 

 petalous species hypogynous ! in the polypetalous 

 arising from the petals ! ovary superior, com- 

 posed of 5 (or 3 or 4) valvate carpels, 1 -celled, • 

 1 -seeded ; ovule anatropal, pendulous from the 

 point of an umbilical cord, arising from the 

 bottom of the cavity ; styles 5 ! seldom 3 or 4 ; 

 stigmas the same number. Fruit a nearly inde- 

 hiscent utricle. Seed inverted, with a rather 

 small quantity of mealy albumen ; testa simple , 

 embryo straight ; radicle superior. 



Distinguished from all monopetalous Orders 

 by their plaited calyx and solitary ovule, sus- 

 pended from the apex of a cord which arises 

 from the base of a 1 -celled ovary, with several 

 stigmas. They are nearly related to Primworts, 

 in their habit, if Armeria is compared with An- 

 drosace, and as is indicated by the opposition of 

 the stamens to the lobes of the corolla ; but they 

 have less albumen and a larger embryo than pro- 

 perly belongs to the Cortusai Alliance, of which 

 they must be looked upon as one of the most out- 

 lying Orders. The economy of the ovule is 

 highly curious ; before fecundation it is suspended 

 from the apex of a cord, or rather strap, which 

 lies over the foramen or orifice through which the vivifying influence of the pollen has 

 to be introduced ; this foramen is presented to the summit of the ceU immediately below 

 the origin of the stigmas, but has no communication with that part of the cell, trom con- 

 tact with which it is further cut off by the overlying strap ; but as soon as the pollen 

 exercises its influence upon the stigmas, the strap slips aside from above the ioramen, 

 which is entered by an extension of the apex of the cell, and thus a du-ect communication 

 is established between the pollen and the inside of the ovule. This phenomenon is ob- 

 scurely hinted at by several writers, but was first distinctly shown me by Decrown and 

 has since been beautifully illustrated by Mirbel, Nouvelks Recherches sur I Ovule, tab. 4. 

 According to Koch, the singular sheath which in Armeria invests the top of the scape, 

 and which Ray supposed to be of the nature of a calyptra, is nothing more than the base 

 of the involucral leaves, in a state of adhesion *,„*«! 

 Many are inhabitants of the salt marshes and sea-coasts of the temperate parts of the 

 world, ^particularly of the basin of the Mediterranean, the southern provinces of the 

 Russian empire, and especially of Afghanistan. The Koollah-i-Huzareh, which forms 

 a large part of the fuel of Cabul, consists of various species of Statice. Others grow 

 from Greenland and the mountains of Europe, to the sterile volcanic regions of Cape 

 Horn A few are found within the tropics ; of these Plumbago zeylamca extends from 

 Ceylon to Port Jackson, and yEgialitis grows among the Mangroves of northern Austral- 

 asia. Vogelia is from the Cape of Good Hope, and Ceratostigma from China. 



Fig COCCXXVIIT.— Armeria vulgaris. 1. calyx and stamens; 2. section of corolla; 3. pistil; 4 

 ovule ; 5. embryo. 



Fig. CCCCXXVIII. 



