This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Annual or perennial herbs, sometimes a little woody below, with entire or sinuately toothed leaves. Peduncles slender, in ours solitary from the axils of the leaves. Calyx campanulate, 5-toothed, in fruit enlarged and bladdery-inflated, membranous, 5-angled, or prominently 10-ribbed and reticulate, wholly inclosing the pulpy berry, its teeth mostly connivent. Corolla yellowish or whitish, often with a darker brownish or purplish center, open-campanulate, or rarely campanulate-rotate, plicate. Stamens inserted near the base of the corolla; anthers oblong, opening by a longitudinal slit. Style slender, somewhat bent; stigma minutely 2-cleft. Seeds numerous, kidney-shaped, flattened, with a thin edge, finely pitted. [Greek, bladder, referring to the inflated calyx.]
* Text contributed to our first edition by Dr. P. A. Rydberg, here somewhat revised.
Probably 75 species, or more. Two are of European origin, and about half a dozen are natives of India and Australia, the rest are American; about 30 occur in the United States. Type species: Physalis Alkekengi L.
* Annuals with branched fibrous roots. † Plants more or less pubescent (except in races of P. barbadensis.) Fruiting calyx sharply 5-angled, more or less acuminate at the summit and sunken at the base; calyx-lobes (at flowering time) lanceolate or acuminate, as long as the tube or longer. Leaves ovate, oblique, acute or acuminate, subentire at the base; upper part repand or suben-tire; fruiting calyx small and short; stem slender, diffuse, sharply angled.
1. P. pubescens.
Leaver cordate, oblique, strongly sinuate to the base; stem stout, obtusely angled; fruiting calyx rounded.
2. P. pruinosa.
3. P. barbadensis.
Fruiting calyx obtusely or indistinctly 5-10-angled; calyx-lobes (at flowering time) triangular, generally shorter than the tube.
4. P. missouriensis.
†† Plants glabrous, or the upper part sparingly beset with short hairs, or a little puberulent when young; fruiting calyx obtusely 5-10-angled, not sunken at the base. Corolla yellow, sometimes with the center a little darker but never brown or purple.
Peduncles generally much longer than the fruiting calyx; leaves sinuately toothed or subentire.
5. P. pendula.
Peduncles scarcely exceeding the fruiting calyx; leaves sharply dentate.
6. P. angulata.
Corolla yellow, with a brown or purple center 7. P. ixocarpa.
** Perennial by thick roots and rootstocks.
† Pubescence not stellate (although in P. pumila of branched hairs).
Pubescence on the leaves none, on the upper part of the stem and the calyx sparse and short, if any. Fruiting calyx ovoid, nearly filled by the berry, scarcely sunken at the base. Leaves ovate-lanceolate to broadly ovate, usually thin.
8. P. subglabrata.
Leaves lanceolate, oblanceolate, or linear.
9. P. longifoha.
Fruiting calyx pyramidal, very much inflated and deeply sunken at the base; leaves broadly ovate, usually coarsely dentate.
10. P. macrophysa.
Pubescence sparse, consisting of flat, sometimes jointed, and in P. pumila branched hairs; in P. virginiana sometimes a little viscid. Fruiting calyx ovoid, scarcely angled and scarcely sunken at the base; leaves thick, obovate or spatulate to rhomboid, subentire. Leaves obovate or spatulate; hairs all simple.
11. P. lanceolata.
Leaves broader, often rhomboid; hairs on the lower surface branched.
12. P. pumila.
Fruiting calyx pyramidal, more or less 5-angled and deeply sunken at the base: leaves ovate to lanceolate, generally more or less dentate.
13. P. virginiana.
Pubescence dense, short, more or less viscid or glandular, often mixed with long flat jointed hairs. Leaves large: blade generally over 2' long and more or less cordate.
14. P. heterophylla.
Leaves less than 2' long, rounded ovate or rhombic, scarcely at all cordate at the base; calyx, peduncles and younger branches with long white flat and jointed hairs.
15. P. comata.
Leaves small, 1'-1 2/3' in diameter, nearly orbicular, sometimes a 1ittle cordate at the base, not coarsely toothed; stem diffuse or prostrate.
16. P. rotundata.
†† Pubescence dense, cinereous, beautifully stellate.
17. P. viscosa.