566 



Botanical Miscellany. 



olyssoldes ; Crucifersa. From the Andes of South America, and probably 

 the largest species of jDraba which exists. — Parmelia enteromorpha; Cryp. 

 iichenes. A lichen found on the branches in the western parts of North 

 America, by Menzies, Douglas, and others. — Poincia?2« Gilliesw ; Legumi- 

 nosae Caesalpinere. A beautiful shrub from the neighbourhood of Quinto 

 and Mendosa in South America. " The flowers have a sickly disagreeable 

 smell, and are supposed by the common people to be injurious to the sight. 

 Hence its vernacular name ' Mai de OjosJ " — Neckera Douglass^'; Cryp. 

 -Miusci. A moss growing on rocks and trunks of trees near the Columbia 

 River, — Grimmwz crispata ; C. ikfusci. A moss from the Cape of Good 

 Hope. — A'tropa rhomboidea ; Solaneee. From the neighbourhood of 

 Buenos Ayres. — Brachymenium pulchrum ; C. Musd. A South African 

 moss. — Colliguaja (from Colliguay, the native name) integerrima, salici- 

 folia, and odorifera; Euphorbidcece. Three shrubs from North America, 

 of which little is known. -^- Gymnostomum Wilsonij C. ilfiisci. Found 

 in Cheshire and Forfarshire. — iemna gibba. The seeds of the different 

 species of iemna are so minute, that it is extremely difficult, if not impos- 

 sible, to comprehend their structure satisfactorily, and germination alone 

 can teach the true nature of the different parts. Mr. Wilson of Warring- 

 ton, in 1827 and 1828, paid the most patient attention to the develope- 

 ment of the seeds of Lemna. He preserved them through the winter in a 

 dry state, and exposed a few of them to germinate in March and April, 

 finding the beginning of the last month the most favourable period. The 

 account is exceedingly interesting, and we shall give it in Mr. Wilson's own 

 words : — 



" Germination of the Seeds of liSmna gibba. When the seeds have 

 been macerated for five or six days, they imbibe sufficient water to enable 

 them to sink to the bottom : previously to this they swim on the surface, 

 and, when almost ready to descend, the upper end of the seed, from which 

 the embryo bursts forth, is turned downwards. 



" After lying at the bottom a few days, the embryo expands, and bursts 

 the inner coat of the seed, elevating its upper portion, which is always 

 circular, with a small rather thick umbo at its centre. I term this part the 

 scutellum, as it seems destined to protect the embryo from injury while 

 breaking through the external covering, which is of a rather firm texture, 

 though much thinner in the part intended for the transmission of the embryo 

 than it is elsewhere. Between this part and the apex of the inner coat of 

 the seed there is at first a considerable vacancy ; and it is only 

 after the rupture of the inner coat that the embryo is sufficiently 

 swelled to arrive at the outer barrier, and force open a passage. 

 {fig- 95.) At the time when that is accomplished the embryo 

 becomes visible, bearing on its summit the scutellum, firmly at- 

 tached, by its centre only, to the lower lip of the cotyledon, and 

 also covering, with a portion of its circumference, the upper one ; 

 which, however, very soon forces the scutellum aside, and projects 

 beyond it. The cotyledon, at first erect, now takes an oblique direction, 

 and ultimately an horizontal one (fig. 96.) ; and soon after its appear- 

 ance the seed rises to the surface of the water. 

 When the embryo was a little more advanced, 

 and the removal of the coats 

 of the seed (fig. 97. «) ef- 

 fected (fig. 98.), the inner 

 coat of the seed, the scu- 

 tellum or upper portion 

 separating from the lower 

 part at a circular fissure, 

 then appears to view. 

 0%.99.») 



