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14 (4

Verbasca. — Koelreuter

Act. Accad. St. Petersb 1781. Part I. p. 249 —

(Koelreuter has written Pamplets 8vo German Zweyte & Dritte Fortsetzung der Nachricht von einigen das Geschlecht — – — versuchen. Leipzig 1764. & 1766. — )

Verbascum phlomoides ♀ (Italy H. Don)
V. Blattaria ♂ (Britain)
Hybrid plants, colour at first flowering like father but disappeared — intermediate between parents in other respects — quite sterile

Crossed varieties chiefly in colour of corolla of above, & hybrids (& likewise in an inverse cross of these varieties) resembled foregoing except in colour of corolla. —

p. 253 V. Thapsus ♀ (Britain)
― phlomoides ♂ (Italy)

Hybrid plants intermediate — Pollen more golden colour than in either parents & consisting (p.254) of small elliptic, empty follicles, scarcely filling the anthers so that at time of flowering, from contraction of integuments

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p. 15 (1 (5

Verbasca

scarcely visible. — Pollen grains immersed in water remained unchanged, whilst those of ♀ & ♂, constantly changed their elliptic into subglobose form — Scarcely one of the hybrid pollen-grains swelled in water —
(Examine unhealthy plants in this point of view)

p. 255 All these hybrids quite sterile
(a) get decorated from July to Sept. with innumerable flowers — The hybrid flowers were scattered in vain with pollen of both parents — This clearly show he observes thy are not varieties of each other. —
N.B Castration of V. Thapsus most difficult except before flower is opened. —

p. 256 Inverse of above, — gave plants quite similar

[62v]

(a) Shows plant not flowering from too much manure &c &c. has no relation to sterility, or some quite different relation —

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Verbasca

p. 257 gives another case, like that at beginning of paper of crossing a yellow variety of V. Lychnitis with V. phoeniceum & hybrids similar to a foregoing one except in colour of flowers. — so that a variety seems to transmit its peculiarities like an ordinary species.

p. 256 & 257.
Gives three cases, where hybrid offspring were similar to inverse experiments described in pamphlet. —

p. 258
V. blattaria ♀
V. Thapsus ♂
Both grow in Britain
Hybrid intermediate & planè steriles

p. do.
V. phomoides ♀ Italy H.
V. Boerhaavii ♂ — S of Europe H.
— inverse failed —
Hybrid offspring quit sterile & intermediate between parents

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Verbasca

p. 259.
V. Boerhaavii ♀
V. phoeniceum ♂ inverse tried on seven flower same day & same year failed (tried on 5 flowers)
offspring intermediate & sterile

p. do.
V. Boerhaavii ♀
V. Lychnitis ♂
inverse tried, on other year on 28 flowers & failed
(tried 7. flowers)
Offspring numerous, sterile, intermediate between parents.

A vast number 53 of experiments enumerated on diffr: species of Verbasca frustra. hitherto failed. —

N.B It is important the number of inverse experiments wh. fail. — it shows that construction of organs greatly interferes with impregnation — many more species would probably cross were it not for this — & som perhaps would more copiously seed. — It is evidently a different consideration from the sterility of the hybrid offspring. —

[64v]

Loudon Encyclop
D. ferox China (White)
D tatula N. America (Blue)
no other difference
(inverse not in)

D. incornis not mentioned by Gärtner —

Kölreuter, J. G. 1781. Verbasca nova hybrida. Acta Academiae Scientiarum Imperialis Petropolitanae 1781 (part 1): 249-270.