In the 16th Botanical Congress of Mexico it was pointed out, that the floral richness of Mexico is the third greatest one on the earth. The actual count of the cormophyta species is getting to ca 22,500, esteemed to reach up to about 30,000 in the state of full exploration. Therefore an intensifying of the field studies, collecting activities and taxonomic/phylogenetic - both morphological and molecular - studies has been decided by the congress, for an effective protection of this extraordinary biodiversity. Rubiaceae is one of the families represented with the highest generic and specific diversity of the Mexican Flora with 102 genera and ca 560-570 species. During the last 15 years 9 new genera and 95 new species have been described showing the further possibilities of a more intensified exploration. With this paper a series of publications is started for a quick and comprehensive introduction of the new results into the scientific knowledge. The first paper contains the description of two new Arachnothryx species and a new variety of Rogiera from Chiapas.
is a neotropical genus including over 100 species of trees and shrubs. In the flora of Mexico it has been represented by a unique species,
. Recently two new species appeared from collections made in Chiapas and Oaxaca states, which have two characters uncommon in the genus, namely the
has 5-merous flowers and the
has unisexual dioiceous flowers, while the overwhelming majority of the
species has bisexual, 4-merous flowers. Therefore it turned to be necessary to modify the generic description.
Two new species were found in the inexhaustible treasury of the collections made by Erik Leonard Ekman in Hispaniola during the 1920s. One is Varronia gonavensis (Boraginaceae) from the Gonave Island of Haiti, the other one is a new Guettarda (G. vulpina) from the Samaná Peninsula of Santo Domingo. Both are endemics to the Hispaniolan flora.
Three new species of the genus Deppea s. str. are discovered and described collected in the federal states Puebla, Veracruz and Chiapas, respectively. Deppea amaranthoides of Veracruz is closely related to the amaranthina-nitida group, but differs in having chartaceous leaves and much larger flowers. D. hoffmannioides of Puebla can be distinguished by its glabrous twigs and leaves and by the unequal reflected calyx lobes. D. densiflora of Chiapas is unique among the small leafed related species in having subsessile inflorescence and flowers.
A new species of the genus Bouvardia belonging to the subgen. Bouvardiastrum, sect. Gymnosiphon was collected by José Pascual in the southern part of the state Oaxaca in Mexico. At first glance it is similar to the polymorphic B. multiflora (Cav.) Schult. et Schult. f. widely distributed in Mexico to El Salvador, but differs from it basically in having leaves with 3–5 veins, white flower and corolla tube glabrous on both sides.
After the revision of the genus
L. and other related genera,
Roigella, Mazaea. Suberanthus, Arachnothryx, Rogiera
of the great American and European herbaria (F, GH, Mo, NY, US, BM, K, S) several taxonomic remarks have been published. Some critical taxa of the collection of Ekman have been also revised. As results three species and two subspecific taxa of Rubiaceae, a Clusiaceae and a Myrtaceae are here described:
from Porto Rico,
of Cuba and
Chiococca motleyana is a new name to replace the laterhomonymChiococca pubescens arising after the transfer of Asemnantha pubescens Hook. f. into the genus Chiococca against the earlier homonyms described by Humboldt and Bonpland ex Roemer and Schultes 1819, and by Standley in 1919. Asemnantha was separated from Chiococca by Hooker f. in 1873, based on its 4-merous flowers clustered into sessile axillary fascicles, against the 5-merous racemiflorous species of Chiococca P. Browne. Later on new Chiococca species were described having 4-merous flowers (C. henricksonii M. C. Johnston 1939, and C. petrina Wiggins 1981) and solitary flowers in the axils. With these new discoveries the morphological diagnostical differences disappeared between the two genera. Recently Motley and co-authors (2005) suggested the unit of the two genera based on the common clade obtained by molecular phylogenetic studies.
Molecular studies carried out by Achille
(2006), revealed the polyphyly within the big genus
and in its relationships. According to the nrDNS ITS sequence analyses the New World
belong to two different clades. Most of the species forms a well defined large clade, but two species (
) belong to the different
-clade as a clearly distinct subclade, characterised by a set of important morphological characters. Based on these evidences the segregation of this second group of the New World
seems to be well argumented under the name of the revalidated and amplified genus of
Rusby, effectuating also the necessary new combinations.
A new species and a new variety of the genus Hoffmannia Sw. were collected in the rich flora of Oaxaca. Hoffmannia silviarum is related to H. psychotriifolia (Benth. in Oerst.) Griseb. and dedicated to the honour of two significant persons in the exploration and understanding of the Rubiaceae flora of Mexico.