92 Mr. Hassall on the S/ruciure of the Pollen Granule. 



lati, liorizontales, interstitia bilinearia. Fructus ignoti, color 

 coccineus; exsiccatus rigidus, chartse minime adhsereus. 

 Hab. ad Port Natal. 



272, Martensia, gen. nov. Frons plana, areolata, avenia, margine 

 fenestrata ; fructus duplex ; sphserospermia longitudinaliter in 

 reticulo simplici serie disposita; capsulse sphsericee, reticulo 

 affixse, sporidia subglobosa foventes. 



M. elegans, Hg. Fronde tenuissima, lobata, segmentis cuneato-rotun- 



datis. 'y^ena- tt^f^'i. ^"^y . 



Frons basi affixa, semi usque pollicaris, tenerrima, tenax, cellulis 



angulatis areolata, margine demumfructificante, clathrato-fene- 



strata. Color amoene roseus fugax. Chartse arete adheerens. 

 Port Natal ad lapides. 

 In memoriam amicissimi Georgii de Martens, auctoris Florae Wiir- 



tembergicce, algarum maris Mediterranei scrutatoris indefessi. 



— He ring. 

 197. Nemalion Natalense, Hg. Fronde filiformi, ramosa, ramis elon- 



gatis, villosis, villis articulatis. 

 Color olivaceus, chartfe arete adliEcrens. Hab. ad Port Natal Point, 



Afr. meridionalis. 

 Fucus minimus, Hg. Fronde plana ecostata, lineari, dichotoma, in- 



tegerrima. 

 Vix pollicaris, fronde semilineam lata, spiraliter torta. 

 Port Natal. 



XIII. — Observations on the Structure of the Pollen Granule, 

 considered principally in reference to its eligibilily as a 

 means of Classification. By Arthur Hill Hassall, 

 M.R.C.S.L., Corresponding Member of the Dublin Na- 

 tural History Society. 



It has often been a matter of surprise to me, that no one of 

 the numerous and gifted votaries of those bright and beau- 

 tiful creations, flowers, which are scattered Avitii so profuse a 

 hand over moor and mountain, on hill and through dale, 

 should have fully investigated the structure of the pollen gra- 

 nule in the various tribes of plants, with a view to ascertain 

 whether it could be rendered available for the purpose of clas- 

 sification. 



Much has indeed been written upon its general anatomy ; 

 but the characters of the granules, as they occur in each ge- 

 nus of jilants, appear to have been scarcely at all considered in 

 this country, and almost the only figures which we possess of 

 individual pollen grains are contained in Lindley's ' Introduc- 

 tion to Botany,' and were derived from a work of Purkinje on 

 the subject*. 



* These figures are but little more than mere outlines, and even in this 

 single particular are generally very far from being correct. 



