500 



PORTULACE/E. 



[Hypogynous Exogens. 



Order CXC. PORTULACEiE.— Purslanes. 



Portulaceae, Jtm. Gen. 313. (1789) in part; A. St.Hil. Mem. Plac. Cent. 42. (1815) ; DC. Prodr. 3, 361. 

 (1828) ; DC. iUm. de la Soc. d'Hist. Nat. de Paris, Aug. (1827) ; Endl. Gen. ccvi. ; Meisner Gen. 

 130. ; Wight Illustr. 2. 41. 



Diagnosis. — SiUnal Exogens, loith the calyx and corolla unsymmetrical §, the latter usually 

 conspicuous, amphitropal ovules, and alternate succulent leaves without stipules. 



Succulent slirubs or herbs. Leaves alternate, seldom opposite, entire, without 

 stipules, often vdih bundles of hairs in their axils. Flowers axillary or terminal, 

 usually ephemeral, expanding only in bright sunshine, 

 imsymmetrical in their calyx and corolla. Sepals 2, 

 cohering by the base. Petals generally 5, either distinct 

 or cohering in a short tube. Stamens inserted along 

 with the petals irregularly into the base of the calyx or 

 hypogj-nous, variable in nmnber, all fertile, sometimes 

 opposite the petals ; filaments distinct ; anthers versa- 

 tile, with 2 cells, opening lengthwise. Carpels 3 or 

 more, combined into a one-celled ovary, which is 

 usually free (or partially adherent) ; style single or 

 none ; stigmas several, much divided ; ovules amphi- 

 tropal. Capsule 1 -celled, dehiscing either transversely 

 or by valves, occasionally 1 -seeded and indehiscent. 

 Seeds numerous, if the fruit is dehiscent ; attached to 

 a central placenta ; albumen farinaceous ; embryo 

 cmwed round the circumference of the albumen, with 

 a long radicle next the hilum. 



Ovary partially adherent in some Portulacas. 



In general the Purslanes are easily recognised by 

 then* succulent condition and gay ephemeral flowers ; 

 but in some the flowers are inconspicuous, and in 

 others the succulence inconsiderable. They, in such 

 cases, would have httle to distinguish them from 

 Cloveworts (Caryophyllacese), except their 2-leaved 

 calyx, and that in truth, combined with the other 

 characters, furnishes the essential mark of the Order. 

 Endlicher, however, extends the limits of the Purslane 

 group much beyond this, admitting a number of peri- V'^^i 

 gynous genera whose flowers are quite sjonmetrical. A;'^" 

 These are spoken of elsewhere. In his ^^ew, the 

 difference between Purslanes and Cloveworts consists 

 mainly in this, that the former have the stamens 

 alternate with the sepals when they are equal to them 

 in number, and the latter opposite xmder the same 

 cu'cumstances. But in Orders where the number of 

 stamens is sometimes indefinite and sometimes has no 

 sort of relation to the sepals, as is, in fact, the case 

 with the whole Portulaceous Order as it stands here, 

 it is plain that such a distinction has no existence. 

 I have, therefore, thought it ad^^sable to reject a 

 portion of Endlicher and Fenzl's Purslanes, in which 

 the perigynous msertion is very marked, placmg them in the Ficoidal Alliance, while 

 all his hypogynous genera \vith symmetrical flowers are conveniently arranged among 

 the Cloveworts. The principal deviation from the general featm'es of 'the Order strictly 

 limited, consists in some species haxang the ovary partially adherent, and the stamens, 

 therefore, perigynous. Such instances seem to connect the Order with the genera 

 just alluded to. From Knotworts (lUecebraceae) the monospermous genera of Pm^- 

 lanes are distinguished by the want of symmetry in theii' flowers, and by the stamens 

 being opposite the petals instead of the sepals. De CandoUe remarks, that Purslanes 



Fig. CCCXLIII.— Portulac^i australis.— ^/uf/ic^t'r. 1. a flower; 2. an e.xpanded corolla ; 3, a pistil j 

 -I a ripe fruit ; 5. a section of it. 



Fig. CCCXLIII. 



