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Pollen characteristics of the tribes Calycophylleae, Cinchoneae, and Hillieae (Rubiaceae)
Author(s) -
Andersson Lennart
Publication year - 1993
Publication title -
nordic journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.333
H-Index - 33
eISSN - 1756-1051
pISSN - 0107-055X
DOI - 10.1111/j.1756-1051.1993.tb00072.x
Subject(s) - reticulate , pollen , biology , botany , type (biology) , palynology , morphology (biology) , rubiaceae , zoology , paleontology
Pollen grains were studied on acetolysed material with the aid of the SEM. They may be classified into four types. Type I is characterized by thick (0.92.1 μm) exine with reticulate surface, by distinct colpi with acute ends, and by distinct ora. It occurs in the genera Alseis, Calycophyllum, Ferdinandusa , and Schizocalyx. Ferdinandusa is further characterized by its lumina being differentiated into two distinct size classes. Type II is characterized by a usually thin (usually 0.7–1.1 μm) exine with foveolate surface, by distinct colpi with obtuse to truncate ends, and by poorly demarcated ora. It occurs in Cinchona, Joosia, Ladenbergia , and Remijia . Pollen grains of Joosia are mostly 4–colporate. Type III is characterized by a thick (1.7–2.0 μm) exine with coarsely reticulate surface, colpi are lacking or short and the ora are clearly demarcated. It occurs only in Capirona . Type IV is characterized by a thin (0.5–0.8 μm) exine with a psilate or foveolate surface and usually indistinct colpi with obtuse ends, and by distinct ora. It occurs in Cosmibuena and Dolicholobium . Pollen grains of Balmea, Hillia, Macrocnemum, Stilpnophyllum , and Wittmackanthus , combining features of Type I and II, do not fit into either of these four groups. It is concluded that both the tribes Calycophylleae and Cinchoneae remain eurypalynous in spite of a recent emendation. It is suggested that pollen characters serve best to characterize genera and small groups of genera. It is further suggested that Type I pollen is plesiomorphic in most or all characteristics.