G38 



IIYDROPIIYLLACE.E 



[Perigynous Exogens. 





Order CCXLIV. HYDROPHYLLACE/E. -Hydrophyls. 



It. Brown. Prodr. 1. 492. (181')), without a name.— Hydrophylleae, Von Martins N. G. el Sp. 2. 138. 

 (1828) ; Bentham in Linn Trans. 17. 267. (1834) j Endl. Gen. cxlvi. ; Alph. DC. Prodr. y. 287.— 

 Hvdroleacea;, R. Brown Prodr. 482. (1810), without a name; Id. in Congo, Kunth in Humb. 

 N. G. et Sp. 3. 125. (1818) , Barll. Ord Nat. 18!) ; Choisy Descr. des Hydroleaci'es (no date) ; Endl. 

 Gen. cxlvii. ; Meisner Gen. p. 272; A. DC. Prodr. 564. Note ; Ed. pr. No. cxxviii. 



Diagnosis. — Cortusal Exogens, with the stamens alternate with the sepals, 2 styles, and a 



cirri/note i/nfloresa nee. 



Small trees, bushes, or herbaceous plants, often hispid. Leaves often lobed, alternate, 

 or the lower ones opposite. Flowers arranged in gyrate racemes or unilateral spikes, 

 or occasionally solitary and stalked in the axils of the leaves. Calyx 

 inferior, persistent, deeply 5-cleft ; the recesses usually augmented with 

 reflexed appendages. Corolla monopetalous, hypogynous, regular, shortly 

 5-cleft, between campanulate and rotate, rarely funnel-shaped. Stamens 5, 

 epipetalous, alternate with the segments of the corolla, inflected in aestiva- 

 tion ; anthers versatile, 2-celled, the cells parallel, dehiscing longitudinally. 

 • (J vary superior, simple, 1- 2-celled ; 

 styles 2, long ; stigmas '2, terminal ; 

 placentae 2, free at their back or 

 united to the shell of the ovary, with 

 two or many amphitropal ovules on 

 their inner face. Fruit capsular, 

 2-valved, sometimes 1 -celled, with a 

 large placenta filling the capsule, 

 sometimes somewhat 2-celled, witli 

 the dissepiments incomplete. Seeds 

 reticulated ; albumen abundant, car- 

 tilaginous ; embryo conical, with its 

 radicle next the hilum. 



The general aspect of these plants 

 is that of Borageworts, which agree 

 in the roughness of their leaves and 

 in their peculiar gyrate, circinate or 

 scorpioid inflorescence. They are, 

 however, known by their undivided 

 1 -celled ovary, terminal style or 

 styles, and ovules (if definite) attached to two stalked fungous placentae, which arise 

 from the base of the cell, having their ovules on their inner face, or (if indefinite) 

 attached to parietal placentae. They are further characterised by the presence, in many 

 species, at the base of each lobe of the corolla, of 2 scales or lamellae, the nature of 

 which is unknown. In general appearance they are also sometimes similar to Polemo- 

 niaceae (Phloxworts). But the large quantity of albumen, the indefinite seeds, the 

 central fungous placentae, are all circumstances that point to Primwurts, with which it 

 seems necessary to associate them ; for the minute embryo of all the genera associated 

 with Hydrophyls, and their hard cartilaginous albumen, forbid their being regarded as 

 more than analogous to either Phloxworts or Boi'ageworts. For many years it has 

 been customary to consider these plants distinct from Hydroleaceae, but 1 cmite agree 

 with M. Alph. De Candolle that there are very slight differences between them. Indeed, 

 upon comparing the distinctions hitherto relied upon, they really amount to this and 

 no more : that in Hydrophyls the ovary is 1 -celled, and in Hydroleaceae 2-celled ; but 

 in all cases among these plants the placentae are a pair of fungous projections from the 

 margin or base of the ovary, and it is their adhesion in various ways that determines 

 whether the cavitv has 1 or 2 cells. In the former edition I pointed out the near affinity 

 of the two supposed Orders, and I now unite them, not seeing how even sectional 

 characters can be found for them. 



Trees or herbaceous plants, found either in the north or among the most southern 

 of the southern provinces of America ; not much known beyond that continent. Nama 



Fig. CCCCXXVII. 



Fig. CCCCXXVII. — Hydrophyllum canadense. 1. a flower; 2. a pistil ; 3. a perpendicular section 

 of the ovary ; 4. a cross section. 5. Section of seed of H. virginianum.— Gartner. 



