OF ARTS AND SCIENCES. 43 



dehiscence of the capsule. The genus should probably bo upheld, but 

 the distinctions between it and Philadelphus are rather slight. Two 

 of them are now brought out, namely, the imbricative aestivation ot 

 the corolla (but this sometimes occurs in Philadelphtts), and the 

 structure of the stigma, which so far as I know is not imitated in 

 Phllaili'lphus. The more superior gyncecium is striking, at least in 

 fruit; but that is a matter of degree. The habit and foliage in this 

 plant and in Philadelphus serpyllifolius are not unlike. Occasionally 

 the petals and some of the filaments persist until the fruit is grown. 



IIOWELLIA, Nov. Gen. Lobeliacearum. 



Flores biformes, pedunculati, emersi amplius corolliferi, submersi 

 corolla depauperata. Calycis tubus lineari-clavatus, usque ad sum- 

 mum apicem ovarii adnatus ; limbo 5-secto, segmentis subsequalibus. 

 Corolla calyccm baud superans, tubo brevissimo bine fisso, lobis 

 oblongis subsequalibus, tria in labium trifidum altius coalitis. Stami- 

 num tubus fere liber, cum stylo leviter incurvus : antherae ovales, 

 duo minores setulis 3 penicillatus, tres majores nudue : stigma bilobum. 

 Ovarium prorsus uuiloculare : placenta? 2 filiformes parietales, pauci- 

 (3-5-) ovulate: ovula superiora adscendentia, inferiora pendula. 

 Capsula clavato-oblonga vel fusiformis, apice contracta, matura mem- 

 branacea, uno latere irregulariter rumpens. Semina pauca, lineari- 

 oblonga, ratione capsula? magna (lin. 2 longa). laevia, ad chalazam 

 calloso-subapiculata. — Herba aquatica ; nunc tota submersa, ramis 

 verticillatim ortis elongatis foliosissimis, foliis lineari-setaceis elongatis 

 plerisque al tern is, floribus axillaribus fere cryptopetalis, capsula liueari- 

 fusiformi calycis lobis lineari-setaceis elongatis superata; nunc apice 

 emersa, foliis subremotis parvis lineari-oblongis saspe 1-2-dentatis, 

 calycis lobis liuearibus sesquilineam longis corollam albam subcequan- 

 tibus, capsula breviore in pedunculo parum longiore. 



Howellia aquatilis. — In stagnant water, on Sauvies Island 

 in Willamette Slough, Oregon ; discovered by Thomas T. and Joseph 

 Howell, who collected in May, 1879, the submersed form, abundantly 

 flowering and fruiting, but the inconspicuous corolla hardly expand- 

 ing; and in August, at another station, specimens with emersed tips 

 to the stems, bearing flowers with well-developed corolla, but much 

 shorter calyx-lobes. This corolla is a line and a half or two lines in 

 length, the limb that of a Lobelia, but with the tube very short and 

 the slit between the two (seemingly) upper petals extending to the 

 base, yet apparently not quite separating them. At the other margin 

 these two petals are manifestly connate with the adjacent ones of the 



