514 PIPERALES. [Hypogynous Exogens. 



Alliance XXXIX. PIPERALES.— Tre Piperal Alliance. 



Diagnosis. — Hypogynous Exogens, with achlamydeous floivers, and a minute embryo^ at or 

 near the outside of a large quantity of mealy albumen. 



The resemblance to each other of the plants included in this AUiance is manifest ; but 

 their affinity to Chenopodals is obscure. It chiefly depends upon the assumption that 

 Piperals stand in near relation to Urticals, and that Chenopodals are the bisexual 

 analogue of the latter. Granting this, which seems to be supported by strong evidence, 

 we must then suppose that Piperals are a lateral sprout from Chenopodals, directing 

 itself, not onwards to the next Alliance, but backwards towards the frontiers of the DicU- 

 nous Sub-class, to which the occasional unisexuaUty of the flowers of Pepperworts and 

 Chloranths evidently points. 



Piperals are clearly indicated by their naked flowers, constantly orthotropal ovule, 

 abundant mealy albumen, and minute embryo, which is either external, or only just 

 within the surface of it. 



Natural Orders of Piperals. 



Ca'i'pel solitary. Ovule erect. Emhryo lying in vitellus. Zeauesl ,q/. prpp^.ppi. 



opposite or alternate, with or ivithout stipules j * 



Carpel solitary. Ovule suspended. Embryo naked. Leaves \-,qj rmr. 



opposite, imth intermediate stipules . ....... 1^^'- ^h^oranthacea. 



Carpels several, distinct. Ovule erect. Embryo lying in vitellus. \ -.Qr, o tt» t, ^ ^ 



Leaves alternate, with stipules | iy». ^aururace^. 



