141 



prominent than in Hottentottum ; sterigmas simple ; spermatia staff- 

 shaped, 9- to ii-thousandths of a milhmetre in length. Reaction of 

 the hymenium from blue becoming vinous-red. Gonidia from 13 to 

 18 mmm. in diameter. 



A thin section of the thallus shows it to be composed of a com- 

 pact medullary tissue of longitudinal fibres, which pass perpendicu- 

 larly to the surface on either side, the gonidial stratum being about 

 one millimetre below the upper surface. After treatment with pot- 

 ash, sulphuric acid and iodine» the hymenium assumes a deep blue 

 color, the hypothecium a pale yellow, and the internal contents of the 

 spermogones a vinous-red, and the hyphae of the thallus become a 

 pale' blue, which is deeper w^hen the section is of some thickness. 



In the only fragment of O. Hottentotiu77t which I have seen, the la- 

 ciniae of the thallus are narrow and elongated, the upper surface is 

 darker than in var. Arizonicuvi and the lower surface uneven but not 

 lacerate, with stiff fibres at the margin. The apothecia are also ciH- 

 ate and the margin is more indexed than in the other. A thin section 

 shows the structure to be the same in both plants, the inferior stra- 

 tum being, however, somewhat narrower in Hottefitottmn ;■ the gonidia 

 all about ijmmm. in diameter. On the application of potash, the 

 gonidial stratum becomes a bright red, a change which does not occur 

 in var, Arizonicitm, The spores in Hottentottum (seen only in the 

 thekes vvhere they often are smaller than w^hen free) are like those of 

 the other plant, but from 9 to iimmm. in length. Reaction of the hy- 

 menium with iodine, blue. The hyphae of the lower stratum are con- 

 tinued into the solid fibrils. 



It is curious that two other Cape lichens, Parmelia 77iolliuscida^ 

 Ach-, and Pertussaria ambigens^ (Nyl.) Tuck., have also been found 

 in the western regions, the one being not uncommon in the Rocky 

 Mountains and the other occurring in Oregon. 



136 Ballast Plants in and near New York City.— I have 



found but little opportunity during the past season to continue the 

 observation of adventive plants introduced with ballast, reported in 

 previous numbers of the Bulletin, (Vol. vii. p. 122). The princi- 

 pal grounds near Communipaw, containing the freshest deposits 

 of ballast have been frequently dug over to destroy weeds, so that 

 there was little chance for any mature growths. No new ballast has 

 been brought there this year, and there are doubtless other places 

 near New York where it has been deposited which if sought out and 

 watched during the next few years would richly repay attentive 

 observation. 



The results of a few visits to the grounds at Communipaw Ferry 

 are given below, with the names of several species which were col- 

 lected in 1880, but omitted by mistake in last year's report. 

 Many, if not most, of those previously reported continue to re-' 

 appear where the ground is undisturbed. Aspenigo procumbens^ Neslia 

 panicidata^ and Sisymbrium Irio were found in considerable masses in 

 places quite distant from where first found ; and Lepidium Draba^ 

 exterminated where it had flourished several years, appeared from 

 fresh seeds in another quarter. 



