496 SEDACEAE 



1. Podostemon Ceratophyllum Michx. Plants olive green, glabrous. Stems 

 0.5-2 dm. long, attached to stonea in running water by disk-like expansions: leaves 

 rigid; blades divided into many narrow segments, the base sheathing the stem: 

 flowers solitary, slender-pedicelled : united filaments much longer than the ovary: 

 capsules oval, 2.5 mm. long. 



In running water, on rocks, Ontario to Minnesota, Maine, Georgia, Alabama and Ken- 

 tucky. Summer and fall. 



2. Podostemon abrotanoides Nutt. Similar to the preceding species in habit, 

 but larger, the stems sometimes becoming 6 or 8 dm. long. Leaves often numerous: 

 blades much divided into almost capillary segments: flowers 2 or 3 together, sessile or 

 short-pedicelled : capsules oblong, 10-ribbed. 



On gravelly river bottoms, Georgia and Florida to Mississippi. Summer. 



FAMILY 2. SEDACEAE Neck. ORPINE FAMILY. 



Herbs or somewhat shrubby plants, various in habit, with mostly succulent 

 tissues. Leaves alternate, opposite or whorled, without stipules: blades thick. 

 Flowers perfect or dioecious, solitary, or usually in cymes. Perianth usually of 

 2 series. Calyx of 4 or 5 persistent sepals, or rarely fewer or more. Corolla of 

 as many imbricated, sometimes united petals as there are sepals, or wanting. 

 Androecium of as many stamens as there are petals, or twice as many. Anthers 

 opening lengthwise. Receptacle with a scale at the base of each carpel. Gy- 

 noecium of as many distinct or partially united carpels as there are sepals. 

 Styles terminal. Ovules in 2 rows along the ventral suture. Fruit membranous 

 or leathery follicles, opening along the ventral suture. Seeds minute, numerous. 

 Endosperm fleshy. Embryo terete. [Crassulaceae DC.] 



Sepals and petals distinct or nearly so: calyx not inflated. 



Stamens as many as the sepals. 1. TILLAEASTRUM. 



Stamens twice as many as the sepals. 



Flowers borne in raceme-like or panicle-like cymes. 2. LENOPHYLLUM. 



Flowers not in raceme-like or panicle-like cymes. 



Petals hooded. 3. DIAMORPHA. 



Petals not hooded. 



Carpels erect: flowers polygamous or dioecious. 4. RHODIOLA. 



Carpels spreading: flowers perfect. 



Carpels typically 4: sepals broader than long. 5. TETRORUM. 



Carpels typically 5: sepals longer than broad. 6. SEDUM. 



Sepals and petals united: calyx inflated. 7. BRYOPHYLLUM. 



1. TILLAEASTRUM Britton. 



Annual small aquatic or mud-inhabiting herbs. Leaves opposite. Flowers soli- 

 tary in the axils. Sepals mostly 4. Petals mostly 4. Stamens free. Carpels usually 

 4, distinct. Ovules, or seeds, few-several. Spring to fall. 



Flowers sessile or nearly so : corolla greenish : follicles with 8-10 seeds. 1. T. aquaticum. 



Flowers manifestly pedicelled: corolla reddish: follicles with 12-20 seeds. 2. T. Drummondii. 



1. Tillaeastrnm aquaticum (L.) Britton. Plants 1-8 cm. tall: leaves 4-6 mm. 

 long; blades linear-oblong: sepals about 0.5 mm. long: petals about twice as long as 

 the sepals. [Tillaea aquatica L.] 



On muddy banks, Nova Scotia to Maryland, Louisiana and Texas, and perhaps in 

 Western North America. 



2. Tillaeastrum Drummondii (T. & G.) Britton. Plants rather smaller than 

 those of T. aquaticum: sepals about 1 mm. long: petals slightly longer than the 

 sepals. [Tillaea Drummondii T. & G.] 



On muddy shores, Louisiana, Texas and New Mexico, and on the Pacific Coast. 



2. LENOPHYLLUM Hose. 



Perennial stout herbs. Leaves alternate or sometimes approximately opposite: 

 blades flattened and somewhat concave. Flowers borne in raceme-like or panicle-like 

 cymes, or rarely solitary. Sepals 5, much longer than wide. Petals 5, yellowish or 

 reddish, contracted below the middle. Stamens 10, those alternate with the sepals 

 partially adnate the petals. Carpels partially united, erect at maturity. 



