262 PORTULACACE^. 



Order XX. PORTULACACEiE. 



By a. Gray ; the genera Leivisia, Calandrinia, Claytonia, and Montia revised by 



B. L. Robinson.^ 



More or less succulent herbs, rarely frutesceut, with entire leaves, hermaphro- 

 dite and regular but mostly anisomerous flowers, calyx and corolla imbricated in 

 the bud ; distinguished, with one or two exceptions, by hypogynous insertion, 

 disepalous calyx not isomerous with corolla, one-celled 2-8-merous ovary with 

 free central or basilar placentae, 2 to 8 introrse stigmas or style-branches, few or 

 many amphitropous ovules, and seeds with a cylindrical embryo curved or coiled 

 in or around mealy albumen, the narrow cotyledons usually incumbent (but not 

 rarely accumbent or oblique in the same genus). Stamens various in number, 

 opposite the petals when of the same number, commonly adnate to their base. 

 No hypogynous disk. No proper stipules. The main exceptions are the half 

 superior calyx of Portulaca, the larger number of sepals in Lewisia, and the 

 reduced number of petals in Calyptridium, &c. Corolla often slightly gamopet- 

 alous. Authesis commonly ephemeral, the withering or colliquescent remains 

 of corolla borne for some time on the ovary or capsule. 



* Lower half or more of ovary and capsule adnate to calyx-tube ; upper part in fruit with 

 the two calyx-lobes circumscissile ; embryo peripheric. 



1. PORTULACA. Petals 4 to 6 and with the more numerous (8 to 30) stamens inserted 

 just where the calyx becomes free, ephemeral. Style-branches 3 to 8, filiform, introrsely 

 stigmatose their whole length. Ovules and seeds numerous, slender-stalked, round-reniform. 



* * Calyx, corolla, and ovary free (hypogynous). 



-1— Shrubby : seeds obovate-oblong, somewhat hook-shaped ; embryo moderately curved in 

 scanty albumen. 



2. TALINOPSIS. Sepals 2, ovate, when dried chartaceo-scarious and nervosa, persistent. 

 Petals 5, oval, soon colliquescent. Stamens about 20, five at base of each petal ; anthers 

 oval. Introrse stigmas or style-branches 3, oblong, shorter than the style ; ovules and 

 marginless seeds numerous ; capsule fusiform-oblong, acuminate ; the coriaceous epicarp 

 3-valved from apex ; chartaceous endocarp 6-valved and filiform sutures often separable from 

 the valves. No bracts. Leaves opposite. 



-)— -I— Herbaceous : seeds reniform, hippocrepiform, or lenticular ; embryo peripheric 

 around the central albumen. 



++ Calyx 2-sepalous, herbaceous, deciduous, sometimes tardily so. 



3. TALINUM. Petals 5, or sometimes 6 to 10, ephemeral. Stamens 5 to 30. Stigmas or 

 short lobes of columnar style 3. Capsule globose or ovoid, 3-valved from top to bottom, 

 many-seeded ; seeds smooth and shining. 



++ ++ Calyx herbaceous (at least in part) and persistent. 



= Style-branches 3 to 8 : capsule circumscissile near the base, thence splitting upwards 

 into short irregular lobes. 



1 In 1887 Dr. Gray (Proc. Am. Acad. xxii. 272-28.5) published a preliminary revision of the N. Am. 

 Portiilacacece. His manuscript notes, however, indicate that he was not satisfied with the treatment 

 of Calandrinia and its allies, and that he contemplated a further revision before publication. On this 

 account the editor has felt somewhat greater liberty in recasting this portion of the order. Although 

 the limits of the four genera above mentioned have been considerably modified in the light of recent 

 publications and some new material, Dr. Gray's specific descriptions have been kept wherever possible. 



